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[RECOVERY] TWRP for Onn Android Tablets (unofficial) - 2019-11-30

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By diplomatic, XDA Ad-Free Senior Member on 8th November 2019, 04:06 AM
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TWRP Custom Recovery for the Onn Android Tablet series

This is the first fully-featured custom recovery for Walmart's MediaTek-based Onn tablets: ONA19TB002, ONA19TB003 and ONA19TB007. TWRP needs no introduction. If you have come here, you probably have some idea of what it is and what it's used for. This TWRP build does not need the bootloader unlocked or VBMeta verification disabled, although it's recommended that you at least unlock the bootloader.

DISCLAIMER
Everything described in this thread is done at your own risk. No one else will be responsible for any data loss, corruption or damage of your device, including that which results from bugs in this software.

FEATURES
  • Decrypted data partition
  • All USB modes functional: MTP, ADB, Mass Storage, OTG, Charging
  • Fast boot time
  • Adoptable storage mounting
  • Firmware image backup and restore
  • Works under locked bootloader
  • Android 9 build fits within the 16MB recovery partition -- no compromises or partition resizing necessary

INSTALLATION METHOD 1
  1. Download the recovery to your PC and unzip the image
  2. Unlock the bootloader (skip if you have already done this)
    1. Enable OEM Unlock in Developer Options in Android Settings
    2. Boot into fastboot mode either by holding vol. up+power to power it on and selecting "Fastboot mode", or by running the 'adb reboot bootloader' command from within Android.
    3. Install fastboot and appropriate drivers on your PC if you have not set those up
    4. Unlock the bootloader with the command
      Code:
      fastboot flashing unlock
      ...and follow the instructions on the screen. This will wipe your data.
  3. Flash the custom recovery with
    Code:
    fastboot flash recovery twrp-3.3.1-ONA19TB002.img
    (use the right file name path for your device)
  4. Reboot to recovery with
    Code:
    fastboot oem reboot-recovery

INSTALLATION METHOD 2
  1. This assumes you are familiar with SP Flash Tool or can figure it out on your own
  2. Download the recovery to your PC and unzip the image
  3. Get the appropriate scatter file for your device. The scatter file may be found in the device's firmware under /system/data/misc.
  4. Set up SPFT Download tab as Download Only. Load your scatter file.
  5. Under the recovery line, double-click Location and open your TWRP image.
  6. Click Download and connect your powered-off tablet to your PC. SPFT will automatically flash the recovery to the emmc and disconnect when finished.

INSTALLATION METHOD 3
  1. Head over to Amazing Temp Root for MediaTek ARMv8, read the requirements and directions, and grab the latest mtk-su.
  2. Open a root shell with mtk-su
  3. Flash the (unzipped) recovery with the command:
    Code:
    dd bs=1048576 if=twrp-3.3.1-0-ONA19TB002.img of=/dev/block/by-name/recovery
    (replace the if= file name with your appropriate recovery image path)
  4. Exit root shell

START RECOVERY
Three methods:
  • On a powered off tablet, hold Vol. up+power for about 3 seconds. In the menu that appears, select "Recovery mode"
  • With Android ADB, use the command 'adb reboot recovery'
  • From Android root shell, use the command 'reboot recovery' or just use any root app with OS reboot features

NOTES
  • Kind of important: Make a backup of your Crypto Footer as soon as you can. This is the encryption key to your data partition. When accessed from TWRP, this key can get "upgraded" so that you will get locked out of Android. TWRP uses a hacky workaround that saves and restores the original footer on every /data decrypt. But that method is not what I would call 100% reliable.
  • Make sure you have a backup of the untouched stock system and vendor images. There are no official firmware packages available to download.
  • Only mount system/vendor partitions in read/write mode if you have unlocked the bootloader. It is recommended to choose to leave system read-only at the startup prompt unless you have a specific reason to modify it. If the bootloader is locked, then dm-verity is enforced.* So merely mounting it once in r/w will cause a boot loop.
  • It's currently not possible to install incremental OTA updates using this TWRP. Use the stock recovery to update the FW. That will only work if you have never mounted system/vendor in write mode.

DOWNLOAD (Nov. 30, 2019)
Current version: 3.3.1-1
Source code
ONA19TB002 | ONA19TB003 | ONA19TB007

ACKNOWLEDGEMENTS
  • The team behind TWRP & OmniROM
  • @tek3195 for testing and feedback on the 8" model
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8th November 2019, 04:07 AM |#2  
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Please post feedback since these are still pretty new and not exhaustively tested. Let me know if I should port it to other models in the series.
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8th November 2019, 04:07 AM |#3  
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Reserved also
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8th November 2019, 04:12 AM |#4  
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grabbing this one too cuz why not
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8th November 2019, 04:22 AM |#5  
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Very nice! I'll download and test the 003 one soon.
I also have a 007 model to experiment with.
I tried about a dozen times to build TWRP and failed miserably LOL. Closest I got was one that would boot but the rotation was all messed up, USB wouldn't work, didn't mount some partitions... Yeah, it was a hot mess.

Do you happen to have sources available?
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8th November 2019, 06:02 AM |#6  
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Hi @NFSP G35,

I'll have the source code soon. Most of the tricks involved patching bootable/recovery. So I need to commit those changes and include the proper patch set from my tree....
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8th November 2019, 12:42 PM |#7  
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Amazing!! Gonna install and test 8" right now.
8th November 2019, 06:58 PM |#8  
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Has anyone tried a GSI on these tablets yet?
8th November 2019, 07:19 PM |#9  
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Quote:
Originally Posted by MishaalRahman

Has anyone tried a GSI on these tablets yet?

I do know @tek3195 , the Onn 8 thread starter, has tried many of them as well as others here, somewhere on that thread he listed his tests and opinion of several of them.
I'm pretty sure others on that thread have also tried GSI's.
8th November 2019, 09:23 PM |#10  
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Quote:
Originally Posted by MishaalRahman

Has anyone tried a GSI on these tablets yet?

I did try both Phhuson vanilla and also Liquid Remix (I'm keeping this one for now). I didn't flash them through twrp, but using fastboot via bootloader.
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9th November 2019, 02:08 PM |#11  
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WoW! AwEsOmE! I cannot wait to try this! THANK YOU!!!!!!
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