[Android Software Development] shadow460:
ROM updating:

If you open the RFinder HAM app and go to "Advanced Settings" it may prompt you for an update. If it's updating the app itself, follow the on screen instructions.

If it's updating the ROM, follow the instructions to download the file, then STOP. Back everything up including the radio memories, then unmount any SD cards you have, power down, and remove them from the radio.

Re attach the battery to the radio and charge it fully. Once it's charged, unplug the USB and remove the radio from the cradle.

ROOTED USERS ONLY (all others skip to "ALL USERS"):

Get the radio into fastboot mode and connect a USB cable. Locate the downloaded zip file that matches the ROM you have, unzip it into a folder on your PC that's easy to find, and then use fastboot to flash *stock* files from that zip file into the radio to replace any files you've patched or modded. Specifically you'll need the boot.img and the vbmeta.img and they MUST match the ROM currently in the radio. Open a command prompt, then change to the directory where your fastboot is installed. I recommend you put the official vbmeta and boot files in this directory.

"fastboot devices" and wait for your B1+ to show up.

"fastboot flash boot boot.img" where boot.img is the official boot image that matches the one in the radio. Double check your typing, then hit enter.

"fastboot flash vbmeta vbmeta" Again, you need to be sure it's the matching official vbmeta.img. Double check typing, then hit enter.

Double check everything.

"fastboot reboot" Your B1+ will boot back into Android.

Go to Settings -> Reset Options -> Erase All Data, then read the text and hit "Reset Phone".

Alternately you can reset from the B1+'s Recovery Menu (power +vol down IIRC, if not try power +vol up).

Sideload the Magisk app. Again, I used 23, which is older but it's the one I understand best.

ALL USERS:

Plug in a live USB cable (preferably to a USB power outlet, not a computer).

Go to settings -> System -> About Phone -> System Upgrade. Click that and choose update from local storage, then choose the update file the radio downloaded or that you received from the customer support team. Follow the instructions. The radio will shut down. You may have to power it up manually. It'll go into a mode that looks like recovery, then it'll say it's updating. If something isn't right the update will abort and generate an error message. If everything is OK the update takes around five minutes. The first reboot hangs on the tower splash screen for a while, so please be patient!

Non rooted users are done. Hooray!

ROOTED USERS:

Once the update is finished, go to your fastboot folder on the PC and replace vbmeta with the empty one you used with the old *rooted* boot.img.

Unpack the new update file, copy it to the radio's internal storage, and use Magisk to patch it. Copy the patched file back to your PC, preferably into the folder with fastboot.

Get the radio into fastboot mode and connect it to your PC with a USB cable.

Use fastboot the same way you did above except this time, flash the patched boot.img and the empty vbmeta.img.

Double check everything you just flashed, then type "fastboot reboot" and hit Enter.

Once the radio loads up, download a root verification app and run it. You should get a superuser request. Hit grant, read the root checker output, and voila!

Next find the RFinder HAM apk and install it. Ideally you should have a backup of it, if not, get it from RFinder.wiki.

Make any other mods you need to make, then reinstall any SIM and SD cards, update the RFinder HAM and IMEI apps if necessary, restore your memories into the RFinder HAM app. Reload your other apps, restore any backups they have, re grant root access as needed, and you're done.