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Android 10 & Custom ROM & Slot A + B

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roel1976

Senior Member
Apr 4, 2011
117
17
Amersfoort
OnePlus 6
Hello Android developers and enthusiasts,

I've been installing ROM since 2011 so I would not call myself a n00b however I seemingly cannot install an Android 10 ROM without issues. So this is a plea for help and advice!

I know you need to have OOS installed before you install a custom ROM so I use Auto Flash ROM to install OOS with Android 9 via System Update. I then boot and set up phone, install update, reboot and then install the OOS android 10 via the System Update. I then have a OOS installed with Android 10.

Why would I use such an elaborate method you may ask? Well, I tried to download latest OOS from OnePlus site and wipe phone and then install OOS but that fails (didn't record the error I'm afraid).

I then download all the ROM + dependencies on an USB stick and use fastboot to flash Mauronofrio TWRP. I then follow the steps in the ROM instructions. For EvolutionX these were:

First Time Install / Clean Flash
- Have OOS 10.3 flashed to both slots!!
- Boot to recovery
- Flash BUILD.zip (TWRP built-in)
- Wipe Cache
- Format data
- Reboot to recovery (optional)
- Flash Magisk.zip (optional)
- Reboot to system & #KeepEvolving

I followed these to the letter but when i rebooted system I got a snapdragon error and it wouldn't even boot into TWRP until I used fastboot to flash boot into TWRP. I also tried HavocROM and same happened.

I did manage to install Syberia using above method but I didn't like the ROM that much unfortunately.

Finally, I've also read up a lot on Slot A and B but it still is not very clear to me. I think I understand it but what happens does not confirm my theories :)

I therefore have some questions:

- Should I be able to wipe my phone and install OOS on a wiped phone and then install a custom ROM?
- When I install ROM and it says "Reboot Recovery" and then install ROM again. But if I check what slot is being used the reboot doesn't seem to change the slot. My assumption was that booting recovery was to install ROM in the other slot. Is that correct?

Any other tips you can give me?

Again, I like to stress I am not new to installing custom ROMs so I am a bit disappointed that this is causing me such grief.

Following some answers I will retry tomorrow so I can give some more details if needed. For now, appreciate any help.
 

mlira1

Senior Member
Jun 17, 2017
94
37
Hello Android developers and enthusiasts,

I've been installing ROM since 2011 so I would not call myself a n00b however I seemingly cannot install an Android 10 ROM without issues. So this is a plea for help and advice!

I know you need to have OOS installed before you install a custom ROM so I use Auto Flash ROM to install OOS with Android 9 via System Update. I then boot and set up phone, install update, reboot and then install the OOS android 10 via the System Update. I then have a OOS installed with Android 10.

Why would I use such an elaborate method you may ask? Well, I tried to download latest OOS from OnePlus site and wipe phone and then install OOS but that fails (didn't record the error I'm afraid).

I then download all the ROM + dependencies on an USB stick and use fastboot to flash Mauronofrio TWRP. I then follow the steps in the ROM instructions. For EvolutionX these were:



I followed these to the letter but when i rebooted system I got a snapdragon error and it wouldn't even boot into TWRP until I used fastboot to flash boot into TWRP. I also tried HavocROM and same happened.

I did manage to install Syberia using above method but I didn't like the ROM that much unfortunately.

Finally, I've also read up a lot on Slot A and B but it still is not very clear to me. I think I understand it but what happens does not confirm my theories :)

I therefore have some questions:

- Should I be able to wipe my phone and install OOS on a wiped phone and then install a custom ROM?
- When I install ROM and it says "Reboot Recovery" and then install ROM again. But if I check what slot is being used the reboot doesn't seem to change the slot. My assumption was that booting recovery was to install ROM in the other slot. Is that correct?

Any other tips you can give me?

Again, I like to stress I am not new to installing custom ROMs so I am a bit disappointed that this is causing me such grief.

Following some answers I will retry tomorrow so I can give some more details if needed. For now, appreciate any help.

Hi!

I had this exact same problem a couple months ago. Rebooting to recovery used to change slots for me, but then it stopped.

What you can do is change active slot manually on Reboot section. By doing this, you don't even have to reboot to recovery in other to flash the other slot (altough I do it just to be safe).

And remember: the rom is flashed on the inactive slot, so after the final flash you gotta change slots one more time.
 
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Reactions: roel1976
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GuestD2559

Guest
When you flash one ROM on top of another different ROM, particularly OOS to custom, always wipe data and not format data, because some custom ROMs do not support being unencrypted in the first time and then encrypt on the first boot. So do it like this:

  • Flash OOS
  • Flash TWRP
  • Reboot recovery
  • Flash OOS
  • Flash TWRP
  • Reboot system
  • Complete initial setup
  • Reboot to recovery
  • Wipe (not format) data
  • Flash custom ROM (start here for dirty flashing ROM update)
  • Flash TWRP
  • Reboot recovery
  • Flash custom ROM
  • Flash TWRP
  • Reboot recovery
  • Flash Magisk
  • Reboot system

I don't like built-in TWRP in custom ROMs. I always use @mauronofrio's TWRP. So regardless if the custom ROM I'm using has TWRP built-in or not, I always use the method above. I didn't have a problem with installing ROMs using his TWRP. Slots always switch when flashing ROM.
 

roel1976

Senior Member
Apr 4, 2011
117
17
Amersfoort
OnePlus 6
So I just booted into TWRP, did standard wipe action: Data, Cache, and Dalvik. I then try to flash the latest OOS zip and I then get this error:

Error applying update: 7 (ErrorCode::kInstallDeviceOpenError)
Updater process ended withL ERROR: 1.
Error installing zip file: '/usbstorage/00, INSTALL/OnePlus6Oxygen_22_OTA_044_all_2002220042_a46425f1bfe43d2.zip


FIXED: I was using TWRP 3.3.1.11 and I then found out there was a newer version: 3.3.1.18 which you can get here: https://sourceforge.net/projects/mauronofrio-twrp/files/Enchilada/

I am now able to install OOS from scratch (ie wiped phone).
 
Last edited:

harshybar

Senior Member
Nov 9, 2007
293
24
21045
OnePlus 8T
When you flash one ROM on top of another different ROM, particularly OOS to custom, always wipe data and not format data, because some custom ROMs do not support being unencrypted in the first time and then encrypt on the first boot. So do it like this:

  • Flash OOS
  • Flash TWRP
  • Reboot recovery
  • Flash OOS
  • Flash TWRP
  • Reboot system
  • Complete initial setup
  • Reboot to recovery
  • Wipe (not format) data
  • Flash custom ROM (start here for dirty flashing ROM update)
  • Flash TWRP
  • Reboot recovery
  • Flash custom ROM
  • Flash TWRP
  • Reboot recovery
  • Flash Magisk
  • Reboot system

I don't like built-in TWRP in custom ROMs. I always use @mauronofrio's TWRP. So regardless if the custom ROM I'm using has TWRP built-in or not, I always use the method above. I didn't have a problem with installing ROMs using his TWRP. Slots always switch when flashing ROM.

I tried this method and everytime I can't seem to flash oos onto the other slot because when it reboots to recovery the folder is encrypted so I can't see which file is the zip. How do I flash the seccond OOS if it shows up encrypted in TWRP.

I have a OnePLus 6 with the latest OOS now because I got into boot loop and i used a flash-all.bat to get back to stock. I also use maronofrio's twrp because that works.
 
G

GuestD2559

Guest
I tried this method and everytime I can't seem to flash oos onto the other slot because when it reboots to recovery the folder is encrypted so I can't see which file is the zip. How do I flash the seccond OOS if it shows up encrypted in TWRP.

I have a OnePLus 6 with the latest OOS now because I got into boot loop and i used a flash-all.bat to get back to stock. I also use maronofrio's twrp because that works.

If you can boot OOS fine, try to do a local update so that both slots have OOS. Then try to flash a custom ROM again using the method I've mentioned.
 

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    Hello Android developers and enthusiasts,

    I've been installing ROM since 2011 so I would not call myself a n00b however I seemingly cannot install an Android 10 ROM without issues. So this is a plea for help and advice!

    I know you need to have OOS installed before you install a custom ROM so I use Auto Flash ROM to install OOS with Android 9 via System Update. I then boot and set up phone, install update, reboot and then install the OOS android 10 via the System Update. I then have a OOS installed with Android 10.

    Why would I use such an elaborate method you may ask? Well, I tried to download latest OOS from OnePlus site and wipe phone and then install OOS but that fails (didn't record the error I'm afraid).

    I then download all the ROM + dependencies on an USB stick and use fastboot to flash Mauronofrio TWRP. I then follow the steps in the ROM instructions. For EvolutionX these were:



    I followed these to the letter but when i rebooted system I got a snapdragon error and it wouldn't even boot into TWRP until I used fastboot to flash boot into TWRP. I also tried HavocROM and same happened.

    I did manage to install Syberia using above method but I didn't like the ROM that much unfortunately.

    Finally, I've also read up a lot on Slot A and B but it still is not very clear to me. I think I understand it but what happens does not confirm my theories :)

    I therefore have some questions:

    - Should I be able to wipe my phone and install OOS on a wiped phone and then install a custom ROM?
    - When I install ROM and it says "Reboot Recovery" and then install ROM again. But if I check what slot is being used the reboot doesn't seem to change the slot. My assumption was that booting recovery was to install ROM in the other slot. Is that correct?

    Any other tips you can give me?

    Again, I like to stress I am not new to installing custom ROMs so I am a bit disappointed that this is causing me such grief.

    Following some answers I will retry tomorrow so I can give some more details if needed. For now, appreciate any help.

    Hi!

    I had this exact same problem a couple months ago. Rebooting to recovery used to change slots for me, but then it stopped.

    What you can do is change active slot manually on Reboot section. By doing this, you don't even have to reboot to recovery in other to flash the other slot (altough I do it just to be safe).

    And remember: the rom is flashed on the inactive slot, so after the final flash you gotta change slots one more time.