What is this "calypso a318uu"

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dorkxperience

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Dec 7, 2021
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Well I bought this Calypso U318AA from a friend for cheap. It was his sons he got new phone. I bought it to root it. I was just going to do the magical root.. I've rooted several other phones in past. The world wide web has very little info well, no info on this thing. It's a Android 10. I'm not sure of even the best way to unlock the bootloader. I know it doesn't have nothing in developers options. On recovery reboot you can do a recovery boot and a fastboot as well as normal boot. Can't find anything but factory at&t stuff. So any info would be great. Thank you
 

mrmazak

Senior Member
Jun 16, 2013
3,252
1,340
Blu Vivo XL
BLU R1 HD
Well I bought this Calypso U318AA from a friend for cheap. It was his sons he got new phone. I bought it to root it. I was just going to do the magical root.. I've rooted several other phones in past. The world wide web has very little info well, no info on this thing. It's a Android 10. I'm not sure of even the best way to unlock the bootloader. I know it doesn't have nothing in developers options. On recovery reboot you can do a recovery boot and a fastboot as well as normal boot. Can't find anything but factory at&t stuff. So any info would be great. Thank you
I just received this phone from at&t. Found out mtk_client will unlock bootloader. so magisk root "should be" available after this unlock. I have not tried yet , i only unlocked bootloader earlier today. will keep looking for anyone else trying this and update as i find any info.
 

mrmazak

Senior Member
Jun 16, 2013
3,252
1,340
Blu Vivo XL
BLU R1 HD
Phh aoap gsi a11 installs and runs good
To clarify, let me tel you all which build version i have installed and outline the steps to get it loaded.


THIS IS NOT INTENDED TO BE STEP BY STEP GUIDE ONLY AN OVERVIEW
WHATEVER YOU DO ON YOUR DEVICE IS AT YOUR OWN RISK



system-squeak-arm32_binder64-ab-vndklite-vanilla
downloaded from :



!. Bootloader must be unlocked.

AT&T removed the enable OEM unlock from developer menu, but there is an excellent work around 'tool' to get around this.
MTK CLIENT will allow you to read (pull) stock firmware off from phone, much like spflash tool does, except with this phone and many other newer phones the manufacture has enabled security and authorization files to block sp flash tool , SOOOO, tools like mtk client try to stay a step ahead.

I only used the GUI options with the client, it was very user friendly , the tool has way more options than i needed to mess with.


2. Before flashing gsi, make sure you have pulled firmware from phone, so you have stock super.img. If you don't you will not be able to restore device when / if you mess up the vendor partition.

3. I disabled vbmeta verification .
will need stock vbmeta from pulled firmware.

boot into bootloader, (adb reboot bootloader , or reboot while holding the volume up button. You should get a boot menu)

Code:
fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img

(the last part need to point to you file location where ever it is)

4. Now we need to move from bootloader to fastboot. fastboot reboot command didn't work for me so needed to boot recovery first, then fastboot.

Code:
fastboot reboot

hold volume up button to get boot menu, select recovery
from recovery select reboot fastboot

in the fastbootd connection you will be able to flash gsi
the system area is not large enough to fit gsi , so you will need to remove the /product partition.

Code:
fastboot delete-logical-partition product
fastboot flash system system-squeak-arm32_binder64-ab-vndklite-vanilla.img


once completed use the screen menu to reboot back to recovery and perform factory reset.

With the exception of needing to use mtk client, the rest of these steps are standard android process. documented in many locations. I go to the android source first for information. \

 

inglele

New member
Aug 30, 2008
4
2
Thanks a lot mrmazak, I'm working on a step by step guide for newbies like me to expand on your steps to unblock and reflash the phone.
I was able to use MRK Client, unlock bootloader and put the phone in fastboot.
The problem I have is to find the right MediaTek driver for the device USB\VID_0E8D&PID_201C

Where did you find them? I tried Google USB driver from ADP but they use different Device ID and all MediaTek driver with same VendorID 08ED have old ProductID instead of 201C.

Any help on MediaTek driver so I can finish the guide and post the link here?

Specifically, I was able to connect via ADB but Fastboot requires a different driver which I'm not able to find :(

Thanks a lot for your help!
 
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mrmazak

Senior Member
Jun 16, 2013
3,252
1,340
Blu Vivo XL
BLU R1 HD
Thanks a lot mrmazak, I'm working on a step by step guide for newbies like me to expand on your steps to unblock and reflash the phone.
I was able to use MRK Client, unlock bootloader and put the phone in fastboot.
The problem I have is to find the right MediaTek driver for the device USB\VID_0E8D&PID_201C

Where did you find them? I tried Google USB driver from ADP but they use different Device ID and all MediaTek driver with same VendorID 08ED have old ProductID instead of 201C.

Any help on MediaTek driver so I can finish the guide and post the link here?

Specifically, I was able to connect via ADB but Fastboot requires a different driver which I'm not able to find :(

Thanks a lot for your help!
Did not have to install any drivers special.
 

inglele

New member
Aug 30, 2008
4
2
Did not have to install any drivers special.
Yes, I had Other \ Android device listed in Device Manager, so I tried disable signed driver and force install of these drivers: https://forum.xda-developers.com/t/...32-64-bit-driver-install-tutorial-m2.3267033/

Now, I have it visible as MediaTek PreLoader USB VCOM Port but if I type "fastboot devices" is not listed.
ADB is able to see it correctly:
adb devices List of devices attached AYMB5PKZCUEUUOSC device

When I restart in fastboot with "adb reboot bootloader" the phone restart correctly in fastboot.

I'm not able to unblock the connection between fastboot tool and phone in fastboot mode, I suspect due to missing / wrong driver.

If you have any idea, it would be great! :)
 
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mrmazak

Senior Member
Jun 16, 2013
3,252
1,340
Blu Vivo XL
BLU R1 HD
Mod Edit: Quote removed since post deleted.

I received 'not enough space" error when flashed gsi, this is why i delete product partition.

I recall there are fastboot commands to list super.img size, but not sure for super sub-partiton size. there are tools to extract the sub-partitons and it will show individual size.

there must be commands for it in fastboot i think, But i do not know them.\
 
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inglele

New member
Aug 30, 2008
4
2
They deleted the previous post, so I'm copy paste the steps from the blog post.

Pre-requirements​

Unlock phone bootloader​

Bootloader must be unlocked to install the new firmware.

MTK CLIENT will allow you to read stock firmware off from phone, except with this phone the manufacture has enabled security and authorization files to block sp flash tool.

Install Python 3.9 from Microsoft Store and Git – Downloading Package and daynix/UsbDk · GitHub, then open a CMD:

mkdir C:\test
cd C:\test
git clone https://github.com/bkerler/mtkclient
cd mtkclient
pip3 install -r requirements.txt
Once installation in complete, start MTK Client with

c:\Test\mtkclient
python mtk_gui
To activate BRUM mode for the phone and connect it to MKT Client

  • Turn off the phone if it’s on.
  • Press Volume UP + Volume DOWN and plug the USB cable.
  • Do not press power button and MKT Client will detect it.
Backup:

  • In the Read partition tab,
  • Select all of them and Save to C:\Test\Firmware\Original
  • It will take about 40min to complete all the operation
Unlock Bootloader

  • In Flash Tools tab,
  • Click on Unlock bootloader button
  • Debug log will show Bootloader: unlock and python windows list
sej - HACC init
sej - HACC run
sej - HACC terminate
sej - HACC init
sej - HACC run
sej - HACC terminate
Progress: |██████████████████████████████████████████████████| 100.0% Write (Sector 0x1 of 0x1, ) 0.03 MB/s
If you restart the phone, you will see a warning that bootloader is unlocked and it will ask you to factory reset the phone.

Install the new firmware​

You need to have Android DevelopersSDK Platform Tools | Android Developers installed to be able to flash the new firmware.

Enable USB Debugging in the phone and connect ADB​

  • Start the phone
  • Perform a Factory Reset
  • Restart the phone and complete the initial wizard
  • Open Settings -> “About Phone” -> Tap the “Build Number” item seven times.
  • You should get a message saying you are now a developer.
  • Settings -> “System” -> “Advanced” -> “Developer Options.”
  • Open the menu and enable “USB Debugging.”
To verify that ADB in installed correctly and is able to connect to the device:

CD C:\Test\Tools
adb version

Android Debug Bridge version 1.0.41
Version 33.0.1-8253317
Installed as C:\Test\Tools\adb.exe

adb devices

List of devices attached
AYMB5PKZCUEUUOSC device
Boot into fastboot with the following command adb reboot bootloader
or reboot while holding the volume up button and select fastboot.

Install Google ADB FastBoot driver in Windows 11​

Download Google USB Driver | Android Developers as they will be needed to connect the device via fastboot. To install the driver, we need to force the installation in Device Manager with these steps:

  • Open Device Manager
  • Right click on Other Devices \ Android device
  • Select “Update Driver” -> “Browse my computer for drivers” -> “Let me pick from the list of available driver
  • Select “Show All Devices” -> “Have Disk
  • Navigate to “C:\Test\Tools\usb_driver_r13-windows” and let Windows load the drivers
  • Select “Android Bootloader Interface” as driver name
  • Test that Fastboot tool is able to interact with the phone
CD C:\Test\Tools
fastboot devices

AYMB5PKZCUEUUOSC fastboot
Next step is to disable vbmeta verification with the following steps:

Firmware update via Fastboot​

  • While the phone is in the FastBoot mode, type the following:
CD C:\Test\Tools
fastboot devices
fastboot --disable-verity --disable-verification flash vbmeta "C:\Test\Firmware\Original\vbmeta.bin"

target reported max download size of 134217728 bytes
sending 'vbmeta' (8192 KB)... OKAY [ 0.204s]
writing 'vbmeta'... OKAY [ 0.189s]
finished. total time: 0.393s
After vbmeta image is flashed, perform:

  • fastboot reboot fastboot to restart the phone and enter fastbootd
  • Check the phone is connecting correctly with fastboot devices
    and force the installation of Android Bootloader Interface in Device Manager if needed.
The following step delete product partition so system partition has enough space:

fastboot delete-logical-partition product

Deleting 'product' OKAY [ 0.016s]
Finished. Total time: 0.016s
This command flash the custom rom on system partition:

fastboot flash system "C:\Test\Firmware\system-squeak-arm32_binder64-ab-vndklite-vanilla.img"

Invalid sparse file format at header magic
Resizing 'system' OKAY [ 0.016s]
Sending sparse 'system' 1/5 (255489 KB) OKAY [ 14.939s]
Writing 'system' OKAY [ 7.651s]
Sending sparse 'system' 2/5 (262100 KB) OKAY [ 15.141s]
Writing 'system' OKAY [ 7.705s]
Sending sparse 'system' 3/5 (262104 KB) OKAY [ 15.001s]
Writing 'system' OKAY [ 7.595s]
Sending sparse 'system' 4/5 (261825 KB) OKAY [ 14.752s]
Writing 'system' OKAY [ 7.711s]
Sending sparse 'system' 5/5 (183741 KB) OKAY [ 10.421s]
Writing 'system' OKAY [ 5.832s]
Finished. Total time: 107.885s
Once flash of new rom is completed, you can restart the phone and it will boot using the new rom.



Original post suggested to perform a factory reset.
WARNING: In my case, a factory reset caused a reboot loop and was not able to

If you want to proceed, in the menu on the screen:

  • Select “Enter recovery” and
  • Select “Wipe data/factory reset
Screen on the phone will show

-- Wiping data...
Formatting /data...
Formatting /cache...
Formatting /metadata...
Data wipe completed.
If you missed the previous screen, or clicked the wrong button/option:

  • restart the phone holding Volume UP,
  • Select fastboot on the phone
  • Type fastboot reboot fastboot to reenter fastbootd screen
  • And repeat the factory reset
Restart the phone and you are up and running.

Restore original firmware​

If you need to restore original rom, use MKT Client tool to write:

  • vbmeta.bin
  • super.bin
then close the tool and restart the phone. It will be like new
 
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ltk6260

Member
May 4, 2022
22
0
hi! hope i can get some help. this is my first time using mtkclient but i can't seem to get it to detect the phone. i'm making sure to follow the steps listed of having the phone off first, then press both volume buttons and plug in the usb. on the phone it eventually pulls up a "select boot mode" where i can use the volume buttons to select recovery mode fastboot mode or normal mode boot. i've tried recovery and fast boot modes as well as just leaving it on that select screen but nothing is detected in mtkclient
thanks!
 

chucklesb8080

New member
Jun 26, 2022
1
0
New to the world of droid but am familiar with modding stuff so I'm a semi-noob I suppose. Found myself getting one of these things from the local dollar general and followed this guide to get rid of all the google crap and hopefully speed it up a bit. Bootloader is unlocked, .img posted above is flashed, and it boots up and seemingly works. Can't figure out how to sideload apps nor can I find any type of write up explaining what to do with the tree and dump file posted above. Any help and/or clarification, greatly appreciated. MTKClient, ADB, and Fastboot are all installed and functional. Using Linux Manjaro.

--chuckles b
 
hi! hope i can get some help. this is my first time using mtkclient but i can't seem to get it to detect the phone. i'm making sure to follow the steps listed of having the phone off first, then press both volume buttons and plug in the usb. on the phone it eventually pulls up a "select boot mode" where i can use the volume buttons to select recovery mode fastboot mode or normal mode boot. i've tried recovery and fast boot modes as well as just leaving it on that select screen but nothing is detected in mtkclient
thanks!

Run mtkclient. With the phone already off, hold down both volume buttons and connect the phone to your computer. You should hear the "usb connected" notification sound on your computer and mtkclient will pick up it. As soon as you hear that chime, release the buttons, set the phone down, and don't touch it. The screen shouldn't come on during this step.

Make sure you're ONLY holding down the volume buttons and plugging it in. Don't touch the power button.

If you're still having issues with it not picking up your phone, go through the standard troubleshooting steps: Recheck you followed every step, restart your computer, try other USB ports, try other cables.

*********

FYI this isn't applicable to this process, but should be noted: This phone has a weird way to get into the recovery menu. You have to hold Vol+ and Power, then select Recovery from the menu, THEN immediately press and hold the Vol+ (or Vol- I don't recall at the moment) and Power buttons again until the recovery menu comes up
 

ltk6260

Member
May 4, 2022
22
0
Run mtkclient. With the phone already off, hold down both volume buttons and connect the phone to your computer. You should hear the "usb connected" notification sound on your computer and mtkclient will pick up it. As soon as you hear that chime, release the buttons, set the phone down, and don't touch it. The screen shouldn't come on during this step.

Make sure you're ONLY holding down the volume buttons and plugging it in. Don't touch the power button.

If you're still having issues with it not picking up your phone, go through the standard troubleshooting steps: Recheck you followed every step, restart your computer, try other USB ports, try other cables.

*********

FYI this isn't applicable to this process, but should be noted: This phone has a weird way to get into the recovery menu. You have to hold Vol+ and Power, then select Recovery from the menu, THEN immediately press and hold the Vol+ (or Vol- I don't recall at the moment) and Power buttons again until the recovery menu comes up
Thanks! that did help.

i was able to get all the way through up to flashing the new rom. I'm getting this error:

fastboot flash system system-squeak-arm32_binder64-ab-vndklite-vanilla.img
Invalid sparse file format at header magic
Resizing 'system' OKAY [ 0.013s]
error: write_sparse_skip_chunk: don't care size 201668900 is not a multiple of the block size 4096
Sending sparse 'system' 1/2 (262140 KB) error: write_sparse_skip_chunk: don't care size 201668900 is not a multiple of the block size 4096
error: write_sparse_skip_chunk: don't care size 201668900 is not a multiple of the block size 4096
OKAY [ 12.568s]
Writing 'system' FAILED (remote: 'No such file or directory')
fastboot: error: Command failed

still can't get past this error. i've confirmed my filename, file extensions, and file location. even checked file permissions. the img file is in the same folder as the fastboot command itself.
i also tried the command using the full c:\ path to the img file but it fails the same.
i then restored the phone to the original super.bin and the phone worked like normal. so i went all the way back through the steps starting from the top but failed at the same final step flashing the system.
 
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still can't get past this error. i've confirmed my filename, file extensions, and file location. even checked file permissions. the img file is in the same folder as the fastboot command itself.
i also tried the command using the full c:\ path to the img file but it fails the same.
i then restored the phone to the original super.bin and the phone worked like normal. so i went all the way back through the steps starting from the top but failed at the same final step flashing the system.

What are you trying to do? What is the purpose or end result you're hoping to achieve?

I ask because this thread is a bit convoluted and "noobs" looking to just root and tinker might come in thinking they have to do all the steps in this thread to get there.

Like someone wanting an oil change overhearing two mechanics rebuilding a transmission, taking notes, especially where they mentioned "oil," then walking away thinking that's what they need to do.

The tools linked above are great. The mtk one, once I was able to get it running, was how I got past the FRP. For anyone wondering, there's an FRP partition that you can just delete with the tool.

If you're just wanting root, see above for unlocking the bootloader, then stop. I'm 90% certain I achieved root by just following the process outlined the official Magisk page on GitHub.

Can I get some OP/MOD thoughts on breaking this thread up into specific guides with the purpose clearly written in the title?
 

ltk6260

Member
May 4, 2022
22
0
What are you trying to do? What is the purpose or end result you're hoping to achieve?

I ask because this thread is a bit convoluted and "noobs" looking to just root and tinker might come in thinking they have to do all the steps in this thread to get there.

Like someone wanting an oil change overhearing two mechanics rebuilding a transmission, taking notes, especially where they mentioned "oil," then walking away thinking that's what they need to do.

The tools linked above are great. The mtk one, once I was able to get it running, was how I got past the FRP. For anyone wondering, there's an FRP partition that you can just delete with the tool.

If you're just wanting root, see above for unlocking the bootloader, then stop. I'm 90% certain I achieved root by just following the process outlined the official Magisk page on GitHub.

Can I get some OP/MOD thoughts on breaking this thread up into specific guides with the purpose clearly written in the title?
I understand your questioning. I'm trying to unlock and load aosp firmware, or frankly, anything other than what this device is loaded with since it's horribly bloated, slow and periodically unstable. this is a play phone, i have two of these phones actually.
 
I understand your questioning. I'm trying to unlock and load aosp firmware, or frankly, anything other than what this device is loaded with since it's horribly bloated, slow and periodically unstable. this is a play phone, i have two of these phones actually.
So is mine. I agree with the bloat, which I thought was weird considering the Android 10 version it comes with (Go) is supposed to be a more streamlined version for lower end phones that lack the processing power.

I tend to not do new ROMs unless it's something with a track record and support like Lineage, but after playing around with it and testing some of the functions with things like WIGL, Termux, LSposed, etc, I'm thinking it might be a good Nethunter phone.
 
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After some extensive Googling, and since I doubt this falls under the "you're flashing the wrong build/version" because there's only one variant of this phone, I'd say it might be possible you're not running the right SDK platform package.

Start Android Studio, go to Settings > Appearance & Behavior > System Settings > Android SDK and make sure you have the right platform packages installed (i.e. Android 10, API 29) and updated.
 
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    After some extensive Googling, and since I doubt this falls under the "you're flashing the wrong build/version" because there's only one variant of this phone, I'd say it might be possible you're not running the right SDK platform package.

    Start Android Studio, go to Settings > Appearance & Behavior > System Settings > Android SDK and make sure you have the right platform packages installed (i.e. Android 10, API 29) and updated.
    1
    i did stop working with this phone already few months ago, but i did compile twrp , if your interested.

    its not real useful , in that the /data partition remains encrypted, so cant do backups, which is the main purpose. but ill link the github source and release in case you want to continue it. \


    device files, including TWRP :: https://androidfilehost.com/?w=files&flid=332377

    device tree :: https://github.com/mrmazakblu/twrp-device-att_u318aa
  • 2
    Phh aoap gsi a11 installs and runs good
    To clarify, let me tel you all which build version i have installed and outline the steps to get it loaded.


    THIS IS NOT INTENDED TO BE STEP BY STEP GUIDE ONLY AN OVERVIEW
    WHATEVER YOU DO ON YOUR DEVICE IS AT YOUR OWN RISK



    system-squeak-arm32_binder64-ab-vndklite-vanilla
    downloaded from :



    !. Bootloader must be unlocked.

    AT&T removed the enable OEM unlock from developer menu, but there is an excellent work around 'tool' to get around this.
    MTK CLIENT will allow you to read (pull) stock firmware off from phone, much like spflash tool does, except with this phone and many other newer phones the manufacture has enabled security and authorization files to block sp flash tool , SOOOO, tools like mtk client try to stay a step ahead.

    I only used the GUI options with the client, it was very user friendly , the tool has way more options than i needed to mess with.


    2. Before flashing gsi, make sure you have pulled firmware from phone, so you have stock super.img. If you don't you will not be able to restore device when / if you mess up the vendor partition.

    3. I disabled vbmeta verification .
    will need stock vbmeta from pulled firmware.

    boot into bootloader, (adb reboot bootloader , or reboot while holding the volume up button. You should get a boot menu)

    Code:
    fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img

    (the last part need to point to you file location where ever it is)

    4. Now we need to move from bootloader to fastboot. fastboot reboot command didn't work for me so needed to boot recovery first, then fastboot.

    Code:
    fastboot reboot

    hold volume up button to get boot menu, select recovery
    from recovery select reboot fastboot

    in the fastbootd connection you will be able to flash gsi
    the system area is not large enough to fit gsi , so you will need to remove the /product partition.

    Code:
    fastboot delete-logical-partition product
    fastboot flash system system-squeak-arm32_binder64-ab-vndklite-vanilla.img


    once completed use the screen menu to reboot back to recovery and perform factory reset.

    With the exception of needing to use mtk client, the rest of these steps are standard android process. documented in many locations. I go to the android source first for information. \

    1
    Thanks a lot mrmazak, I'm working on a step by step guide for newbies like me to expand on your steps to unblock and reflash the phone.
    I was able to use MRK Client, unlock bootloader and put the phone in fastboot.
    The problem I have is to find the right MediaTek driver for the device USB\VID_0E8D&PID_201C

    Where did you find them? I tried Google USB driver from ADP but they use different Device ID and all MediaTek driver with same VendorID 08ED have old ProductID instead of 201C.

    Any help on MediaTek driver so I can finish the guide and post the link here?

    Specifically, I was able to connect via ADB but Fastboot requires a different driver which I'm not able to find :(

    Thanks a lot for your help!
    1
    They deleted the previous post, so I'm copy paste the steps from the blog post.

    Pre-requirements​

    Unlock phone bootloader​

    Bootloader must be unlocked to install the new firmware.

    MTK CLIENT will allow you to read stock firmware off from phone, except with this phone the manufacture has enabled security and authorization files to block sp flash tool.

    Install Python 3.9 from Microsoft Store and Git – Downloading Package and daynix/UsbDk · GitHub, then open a CMD:

    mkdir C:\test
    cd C:\test
    git clone https://github.com/bkerler/mtkclient
    cd mtkclient
    pip3 install -r requirements.txt
    Once installation in complete, start MTK Client with

    c:\Test\mtkclient
    python mtk_gui
    To activate BRUM mode for the phone and connect it to MKT Client

    • Turn off the phone if it’s on.
    • Press Volume UP + Volume DOWN and plug the USB cable.
    • Do not press power button and MKT Client will detect it.
    Backup:

    • In the Read partition tab,
    • Select all of them and Save to C:\Test\Firmware\Original
    • It will take about 40min to complete all the operation
    Unlock Bootloader

    • In Flash Tools tab,
    • Click on Unlock bootloader button
    • Debug log will show Bootloader: unlock and python windows list
    sej - HACC init
    sej - HACC run
    sej - HACC terminate
    sej - HACC init
    sej - HACC run
    sej - HACC terminate
    Progress: |██████████████████████████████████████████████████| 100.0% Write (Sector 0x1 of 0x1, ) 0.03 MB/s
    If you restart the phone, you will see a warning that bootloader is unlocked and it will ask you to factory reset the phone.

    Install the new firmware​

    You need to have Android DevelopersSDK Platform Tools | Android Developers installed to be able to flash the new firmware.

    Enable USB Debugging in the phone and connect ADB​

    • Start the phone
    • Perform a Factory Reset
    • Restart the phone and complete the initial wizard
    • Open Settings -> “About Phone” -> Tap the “Build Number” item seven times.
    • You should get a message saying you are now a developer.
    • Settings -> “System” -> “Advanced” -> “Developer Options.”
    • Open the menu and enable “USB Debugging.”
    To verify that ADB in installed correctly and is able to connect to the device:

    CD C:\Test\Tools
    adb version

    Android Debug Bridge version 1.0.41
    Version 33.0.1-8253317
    Installed as C:\Test\Tools\adb.exe

    adb devices

    List of devices attached
    AYMB5PKZCUEUUOSC device
    Boot into fastboot with the following command adb reboot bootloader
    or reboot while holding the volume up button and select fastboot.

    Install Google ADB FastBoot driver in Windows 11​

    Download Google USB Driver | Android Developers as they will be needed to connect the device via fastboot. To install the driver, we need to force the installation in Device Manager with these steps:

    • Open Device Manager
    • Right click on Other Devices \ Android device
    • Select “Update Driver” -> “Browse my computer for drivers” -> “Let me pick from the list of available driver
    • Select “Show All Devices” -> “Have Disk
    • Navigate to “C:\Test\Tools\usb_driver_r13-windows” and let Windows load the drivers
    • Select “Android Bootloader Interface” as driver name
    • Test that Fastboot tool is able to interact with the phone
    CD C:\Test\Tools
    fastboot devices

    AYMB5PKZCUEUUOSC fastboot
    Next step is to disable vbmeta verification with the following steps:

    Firmware update via Fastboot​

    • While the phone is in the FastBoot mode, type the following:
    CD C:\Test\Tools
    fastboot devices
    fastboot --disable-verity --disable-verification flash vbmeta "C:\Test\Firmware\Original\vbmeta.bin"

    target reported max download size of 134217728 bytes
    sending 'vbmeta' (8192 KB)... OKAY [ 0.204s]
    writing 'vbmeta'... OKAY [ 0.189s]
    finished. total time: 0.393s
    After vbmeta image is flashed, perform:

    • fastboot reboot fastboot to restart the phone and enter fastbootd
    • Check the phone is connecting correctly with fastboot devices
      and force the installation of Android Bootloader Interface in Device Manager if needed.
    The following step delete product partition so system partition has enough space:

    fastboot delete-logical-partition product

    Deleting 'product' OKAY [ 0.016s]
    Finished. Total time: 0.016s
    This command flash the custom rom on system partition:

    fastboot flash system "C:\Test\Firmware\system-squeak-arm32_binder64-ab-vndklite-vanilla.img"

    Invalid sparse file format at header magic
    Resizing 'system' OKAY [ 0.016s]
    Sending sparse 'system' 1/5 (255489 KB) OKAY [ 14.939s]
    Writing 'system' OKAY [ 7.651s]
    Sending sparse 'system' 2/5 (262100 KB) OKAY [ 15.141s]
    Writing 'system' OKAY [ 7.705s]
    Sending sparse 'system' 3/5 (262104 KB) OKAY [ 15.001s]
    Writing 'system' OKAY [ 7.595s]
    Sending sparse 'system' 4/5 (261825 KB) OKAY [ 14.752s]
    Writing 'system' OKAY [ 7.711s]
    Sending sparse 'system' 5/5 (183741 KB) OKAY [ 10.421s]
    Writing 'system' OKAY [ 5.832s]
    Finished. Total time: 107.885s
    Once flash of new rom is completed, you can restart the phone and it will boot using the new rom.



    Original post suggested to perform a factory reset.
    WARNING: In my case, a factory reset caused a reboot loop and was not able to

    If you want to proceed, in the menu on the screen:

    • Select “Enter recovery” and
    • Select “Wipe data/factory reset
    Screen on the phone will show

    -- Wiping data...
    Formatting /data...
    Formatting /cache...
    Formatting /metadata...
    Data wipe completed.
    If you missed the previous screen, or clicked the wrong button/option:

    • restart the phone holding Volume UP,
    • Select fastboot on the phone
    • Type fastboot reboot fastboot to reenter fastbootd screen
    • And repeat the factory reset
    Restart the phone and you are up and running.

    Restore original firmware​

    If you need to restore original rom, use MKT Client tool to write:

    • vbmeta.bin
    • super.bin
    then close the tool and restart the phone. It will be like new
    1
    After some extensive Googling, and since I doubt this falls under the "you're flashing the wrong build/version" because there's only one variant of this phone, I'd say it might be possible you're not running the right SDK platform package.

    Start Android Studio, go to Settings > Appearance & Behavior > System Settings > Android SDK and make sure you have the right platform packages installed (i.e. Android 10, API 29) and updated.
    1
    i did stop working with this phone already few months ago, but i did compile twrp , if your interested.

    its not real useful , in that the /data partition remains encrypted, so cant do backups, which is the main purpose. but ill link the github source and release in case you want to continue it. \


    device files, including TWRP :: https://androidfilehost.com/?w=files&flid=332377

    device tree :: https://github.com/mrmazakblu/twrp-device-att_u318aa