- Recovery:
adb reboot recovery- With the phone off, press and hold
Volume Up+Power. Sometimes this doesn't work and the phone ends up booting Android normally.
- Download Mode (with bootloader lock & unlock options): With the phone off, hold both volume keys & plug the phone to a computer.
- Download Mode (only download):
adb reboot-bootloader
Additionally, the phone can always be forced to reboot by holding Volume Down + Power for some seconds.
The process is pretty much the same as in any other Samsung phone. Remember that this will perform a factory reset.
- Make sure your phone has internet connection
- Enable developer options and turn on OEM unlocking.
- Shut down the phone & boot into download mode
- Unlock the bootloader by holding
Volume Upto access the unlock menu & then confirm the action withVolume Up.
You can use Odin (Windows) or Heimdall (Windows/Linux).
Before flashing any partition, it's suggested to first flash an empty vbmeta image. If you don't, the bootloader may refuse to boot the device.
Due to a bug in the bootloader, recovery and boot images need to be "fixed" before being flashed, otherwise the phone will refuse to boot them with a "SECURE CHECK FAIL" error. More info in this repository.
TWRP is available for this device but there are some things you must know:
- If you are on the stock firmware (OneUI), the recovery is replaced by the stock one on each boot. You must immediately hold volume up after flashing TWRP to boot directly into it.
- It's not able to access the internal storage nor anything in
/dataunless you disable encryption.
More information can be found on TrebleDroid's Wiki.
- XDA Developers Forum -Most threads are for the Exynos Galaxy A20, there's not much stuff for the A20s
- A20s Telegram Group -Here you can find more step-by-step instructions and get help from other users