[Samsung Galaxy A20 Guides, News, & Discussion] physwizz:
Useful videos

Instructions

A. Prepare boot image

1. Download magisk manager apk

2. Download the exact firmware (including upgrade date) for your device from https://samfrew.com or https://www.samfirmware.net/ or https://www.full-repair-firmware.com/search?q=A20 or

https://samfw.com/

3. Use zarchiver to copy AP_20xxxxxxxx.md5 to download directory. It will extract it from the zip.

4. Rename AP_20xxxxxxxx.md5 to AP_20xxxxxxx.tar and extract using zarchiver

5. Copy boot.img.Iz4 to download directory and extract (resulting in boot.img)

6. Use magisk manager to patch boot.img (use top install) result magisk_patched.img

(If using Magisk (Canary) patch, options should be remove dm-verity and not via recovery, but allowing Persist Encrypt.)

7. Rename magisk_patched.img to boot.img

9. Use zarchiver to compress boot.img to boot.tar. If you have a A205xx June firmware (U2 bootloader), you can use my one of you're willing to take a risk. View attachment 4913059. Just unzip it first.

9a. For a20e users, try this boot.img https://xdaforums.com/showpost.php?p=81649257&postcount=260

10. Copy boot.tar to Windows pc or Windows Virtualbox.

11. On phone developer options in settings unlock OEM and enable usb debugging

(If using Linux

9. Don't compress `boot.img`

10. install heimdall flash with `sudo apt install heimdall-flash`, if you want front-end install it with `sudo apt install heimdall-flash-frontend`)

B. Unlock bootloader

Useful video

12. Backup data. It will be wiped.

13. Turn phone off

14. Hold vol- and vol+ and plug in power cable attached to pc then release vol up to enter unlock screen.

15. Follow the instructions to unlock

(You might need to long press vol up to unlock bootloader)

vol + to select yes to confirm.

17. Press power key to unlock bootloader.

18. Reboot and reactivate developer options and enable usb debugging. Don't enter too much data at this stage as you will lose it again later.

C. Flash boot image.

19. Turn phone on in bootloader (download) mode (Hold power and vol+ to enter recovery mode then select bootloader download mode)

20. Connect phone to computer.

21. Use Odin in Windows to add boot.tar to phone. (Select AP). Some people recommend adding the other firmware parts to their slots at the same time.

22. Restart phone

23. select bootloader

24. Select factory reset (this will wipe data)

25. Restart phone

26. install data

26. install magisk manager

27. If green phone is rooted.

View attachment 4802665

28. Of red select install/direct install

29. Advanced tick both.

30. Install root checker and verify root

If Something Goes Wrong

Go here

https://xdaforums.com/galaxy-a20/how-to/crash-recovery-t4068369

If you get a DTBO error after updating Magisk, flash this vbmeta https://drive.google.com/file/d/1-dogButfxKGlx_x2tSROOBDiq90SDlmc/view

(If using Linux

To flash:

20. Detect device with `heimdall detect`

21. Flash the `boot.img` with `heimdall flash --BOOT {location of the boot.img, you can also just drop the file into terminal and terminal should auto-fill it}` ex: `heimdall flash --BOOT '/home/utku/Programlar/ext/boot.img'`

P.S: an easy way to boot into download mode is `adb reboot bootloader`)

If you want to remove the warning messages on the boot screen

try this.

https://xdaforums.com/galaxy-a30/how-to/hide-bootloader-warning-unlocked-t3954589

The images shown on the A30 thread aren't suitable for the A20 so I have included some better ones here.

View attachment 4803752

View attachment 4803753

You can use this param.tar to make these changes easier.

https://xdaforums.com/showpost.php?p=80169262&postcount=91

You can now move on to install TWRP

This TWRP was originally designed for Android 9 but works perfectly with Android 10 and also has MTP built-in.

https://xdaforums.com/galaxy-a20/development/recovery-twrp-3-3-1-0-galaxy-a10-exynos-t4013481

https://xdaforums.com/t/physwizz-collection.4253081/