Screwed up while updating (rooted) phone and now won't boot

[Mgssidley]

I just screwed up when attempting an update. I had the update downloaded but did not install it.
Then I continued to install the A/B retention script and Magisk to the inactive slot and rebooted.
Now my phone fails to boot, and gets stuck continuously loading.

Is there something I can do in TWRP to resolve this?

 

[Macusercom]

You can try to flash the Magisk uninstaller in TWRP and see if it fixes your issue. Maybe you lost root on one partition and some Magisk modules that are still installed are putting your phone into a bootloop.

 

[Mgssidley]

I'm unable to mount any partitions to get the uninstaller zip on my device. I was able to sideload the zip however the Magisk Installer was also unable to mount partitions.

Edit: I changed the slot from B -> A in TWRP then rebooted and it resolved this!

 

[djsubterrain]

I'm unable to mount any partitions to get the uninstaller zip on my device. I was able to sideload the zip however the Magisk Installer was also unable to mount partitions.

Edit: I changed the slot from B -> A in TWRP then rebooted and it resolved this!

Was just about to suggest that, glad you resolved it but you still have a broken slot, you should be able to fix it by flashing the rom, flashing TWRP and magisk, change slot and repeat. You might need a usb drive attached as changing the slot will usually made the data partition not visible so you won't see your files if they're on the phone.

To be honest, I thought flashing the stock rom will flash it to both slots (it shows this during flash) so I'm not sure what you did that broke it.

 

[Mgssidley]

Was just about to suggest that, glad you resolved it but you still have a broken slot, you should be able to fix it by flashing the rom, flashing TWRP and magisk, change slot and repeat. You might need a usb drive attached as changing the slot will usually made the data partition not visible so you won't see your files if they're on the phone.

To be honest, I thought flashing the stock rom will flash it to both slots (it shows this during flash) so I'm not sure what you did that broke it.

I'm actually on stock and doing an OTA update. After it booted up I was able to install the update, A/B retention script, and Magisk (to inactive slot). It rebooted successfully after that, should I still be concerned about a broken slot?

Edit: On closer look, Magisk did not install properly and I'm unable to access internal storage from TWRP to reinstall it.

 

[Joker123##]

I just screwed up when attempting an update. I had the update downloaded but did not install it.
Then I continued to install the A/B retention script and Magisk to the inactive slot and rebooted.
Now my phone fails to boot, and gets stuck continuously loading.

Is there something I can do in TWRP to resolve this?

You didn't install the ota but you installed magisk to inactive slot?