[General Questions and Answers] kadu01:
Try this at least worked on my CHUWI SurPad, Android 10 CPU: MT6771 (MediaTek) and should work on most MediaTek (mt2601, mt6261, mt6572,... check https://github.com/bkerler/mtkclient/tree/main/mtkclient/payloads )

This will work only on MediaTek and you can achieve this:

- Unlock bootloader (it allows you to modify boot partition) without factory wipe (this would happen using fastboot method)

- Modify boot partition via Magick app

1) Unlock bootloader + backup flash partitions

Get familiar with mtkclient (https://github.com/bkerler/mtkclient)

It is tool that can read/write content of flash. Compile it on your linux or windows. FYI Im describing steps in GUI mode but if you have only working ./mtk binary you can do the same but need to read documentation.

Shutdown your tablet, disconenct USB cable from PC to tablet.

Run ./mtk_gui tool and follow its instruction in console you need to get into BROM mode (it is not fastboot mode nor recovery mode, it is special mode that works only MediaTek chips and usually cannot be used. Anyway this program mtkclient using some exploit to get there due to some bugs). It also means most likely that even bricked devices could be "restored" if someone tried modify recovery partition and bricked by replacing it with original one due to dm_verity protection [you can ask me :) I dumped my device])

Power off the phone before connecting.

For brom mode, press and hold vol up, vol dwn, or all hw buttons and connect usb.

For preloader mode, don't press any hw button and connect usb.

If it is already connected and on, hold power for 10 seconds to reset.

at this stage you should be in this MTK GUI connected and navigate to read tab and save all yourflash partitions. or at least boot.bin, vbmeta.bin, recovery.bin - you can restore them later if any failure.

Also navigate last tab and click unlock bootloader (this wont erase your data at all)

reboot your device (either with ./mtk reset) or holding 10 sec power button and boot back to android 10. In boot screen you will see some warning that device has bootloader unlocked and 5 sec delay before boot.

2) Modify extracted boot.bin with latest Magisk

Download apk here https://themagisk.com/magisk-app/ and install to your andriod (you can use adb push from laptop via connecetd usb cable [need enabled developer mode), or simply copy to sd card and install from there) also copy boot.bin you dumped from previous step 1)

Run Magisk click to install in Magisk section (and select your boot.img file on sdcard or anywhere where you stored it inside your tabled device) and click "Let's go" - this will do some magic inside boot image which enables Magisk to be your root provider for the apps (something like sudo or su). So patched image is stored my location was /storage/emulated/0/Download/magisk_patched-25205.img

Copy this file back to your laptop somewhere

Shutdown your tablet again and unplug usb cable

3) Disable dm_verity + rewrite boot partition using mtk

Boot your laptop to BROM mode again as described in step 1)

to install patched boot.img (now magisk_patched-25205.img) you can use that mtk_gui and same for overwriting vbmeta partition

for disabling dm_verity you need use vbmeta_empty.bin (it is inside mtkclient directory)

No you can reboot your device and should boot.

Run magisk again and you should see now that choices "Superuser" and "modules" are available.

DONE..

you can also patch recovery.bin with your favority TWRP or another (i havent done this)

you can get root access by installing any sshd client and accesing to it, or simply in adb shell type su :) and magisk will ask you to grant it