How To Guide [GUIDE][ROOT][MAGISK v22.0+] Samsung Galaxy A02s SM-A025G

[Android-OS]

This guide was made prior to there being a working custom recovery for this device. I highly recommend installing @afaneh92 TWRP in this thread and then simply flash magisk from recovery.​

I purchased this phone a few days ago for around £120 - Bargain.
I have spent a few evenings trying to obtain root - and finally managed to achieve it with Magisk

Full data wipes are required during the process (please backup first)
Knox will trip but safetynet passes and google pay working once magisk hide enabled

Based on the Samsung specific guide provided on Magisk Github - with a few minor differences.

I have uploaded all of the tools and files used to my personal onedrive folder -

Make sure your device is on the latest firmware and download the zip
- I used SamFwTool version 1.21.0 to download the BTU Firmware for SM-A025G A025GXXU1AUA3

• Install Magisk apk on your device.
• Extract the AP _ tar.md5 from the downloaded firmware .zip using 7zip
• Transfer the AP to your device and Patch it with Magisk , then copy back to your computer.
• Enable OEM Unlock and Unlock the bootloader the instructions from magisk git are below, for those that need a reminder.

Spoiler: Unlocking Bootloader

Unlocking bootloader on modern Samsung devices have some caveats:

Allow bootloader unlocking in Developer options → OEM unlocking
Reboot to download mode: power off your device and press the download mode key combo for your device
Long press volume up to unlock the bootloader.
This will wipe your data and automatically reboot.

If you think the bootloader is fully unlocked, it is actually not! Samsung introduced VaultKeeper, meaning the bootloader will still reject any unofficial partitions before VaultKeeper explicitly allows it.

Go through the initial setup. Skip through all the steps since data will be wiped again later when we are installing Magisk. Connect the device to Internet during the setup.
Enable developer options, and confirm that the OEM unlocking option exists and is greyed out. This means the VaultKeeper service has unleashed the bootloader.

This is where we deviate from the magisk guide... as when I flashed the magisk patched AP along with the BL CP and CSC, you get a vbmeta error and it simply reboots to stock. Magisk seems to patch the vbmeta file and I tried replacing the vbmeta with the stock version from the firmware zip but that also was fruitless.

• Extract the boot.img from magisk patched AP
• Extract recovery.img.lz4 and vbmeta.img.lz4 from the stock (unpatched) AP file
• 7zip - create a new TAR, adding only those 3 files. Boot.tar will suffice for filename
• Odin 3.14.4 - uncheck auto reboot and then Flash boot.tar in the AP section (CSC, HOME CSC, CP, BL not required - as the device and download are using the latest firmware)

The next part is essential and doing it wrong will again, result in no root....
I mistakenly pressed power up and it loaded fastboot... booting direct to recovery from fastboot again, results in no root.

• Hold volume down and power to reboot...
• As soon as the screen turns black indicating it is rebooting let go of volume down and hold power and volume up
• Release power button when you see the android logo but continue to hold volume up
• Release volume up when the unlocked bootloader warning appears
• Tap the power button once to skip that warning
• Stock recovery should now appear
• Select wipe data / factory reset
• Reboot system
• Setup as usual and install the magisk apk
• 

Update 10April2021: Since doing this quite a few times, I've actually had most success with Magisk 22.0 (I initially went with Canary - but stock is less hit and miss and if you do it exactly like the steps above you will get root.