[Honor 8 Guides, News, & Discussion] deadko:
This guide is for update within versions if you are rooted, if not, simply download and install de ota or with FF.

If you update to B394 from any version, downloading the last complete packet in update system, it locks the bootloader !!! be advised

If you update to B399 or B401, B402 from B394, downloading the last complete packet in update system, DO NOT LOCK the bootloader !!! good news

My first problem was when I was in B380 and rooted , the b389 ota arrived...then I unroot, put stock recovery and unistalled busybox, but ota failed at 8%

The solution to this :

1 - flash stock recovery from version you have

2 - download the last complete packet in update system , for me 2.41 Gb, not the ota

3 - (optional but useful for future) connect to pc and copy the 3 files downloaded the update in HWOUC to pc

4 - make the normal update in update system

7 - copy supersu 2.82.zip original file or Magisk to SD

8 - Flash last twrp recovery twrp-3.1.1-1-frd , enter in twrp recovery and:

9 - Tick the option "Keep vendor partition mounted" inside OpenKirin in Settings (last option in settings) for me is ticked as default

10 - Make a backup of boot (for future) if you want

11- flash supersu 2.82 original or Magisk

12 - reboot and it's done!!!!!!!!

Update to B394

if you have done all the process and you want now to update to b394, you can uninstall first supersu within options menu saying yes to all questions when uninstalling and without errors or bad uninstallation; then, delete binaries of busybox, flash stock recovery and try to install ota...for me the ota not installed and done with errors.

Then I installed b394 full and locked my bootloader, forcing me to format all because i unlocked the bootloader (remember to activate oem bootloader unlock on and usb depuration on).

After installing the same twrp recovery, I tested the magisk v14 and works perfect, but with an inconvenient, you have to disable the option of magisk manager "magisk hide" to work with fingerprint ,At version 15.3 I didn't see this error.

B394 to B399

Tried the uninstaller of magisk flashed with twrp to unroot and then put the stock recovery and failed, then I flashed stock boot and failed ....finally it worked downloading the last complete packet in update system.Then the habitual, flash twrp recovery, magisk v15.3 from twrp and magisk manager v5.5 in android...and worked perfect

B399 to B401

This time I only unistalled binaries from busybox and flashed stock recovery; then launched Full update (2.41 Gb) without problems.Then flashed twrp, magisk 15.3 from twrp as usual and nothing more...magisk manager detected all ok and I have a rooted device again.

B401 to B402

Simplified the process, now only flash the stock recovery 401 and make the full update packet (2.41Gb). Then flash twrp, enter in twrp, flash magisk 16.0, reboot and that's all. Install busybox script, adaway hosts and done.

Notes:

1 - If the system downloaded automatically the small ota update. you must to try to update with an obvious error, then you can download the full update packet.

1 - the installation of magisk is simple, in twrp flash the magisk.zip , reboot and install magisk manager to control all. This is another app to root and don't need supersu. The advantages to make this is magisk hide, it permits to work with apps that can't work if your phone is rooted.