Awesome. So you started from 10, sideloaded to whichever slot, flashed the script to the same partition, format data and it worked?
That's correct. When I tried to flash a patched boot image for magisk (perhaps I had the wrong file, yesterday was a long day.) I bricked it again so I've listed the steps in detail.
Started from MSM flashing android 10, because I bricked my device like 12 times, lol.
Went from there to OS to unlock the bootloader.(If your device was previously unlocked, then make sure you setup using mobile data or the option may be greyed out.)
after initial android setup having selected mobile data instead of wifi, skipping google account setup, and entering a pin... basically and as soon as it would allow me to, i swipe down from top and use the gear icon to enter settings.
settings->about phone
accessed developer options by tapping build number 7 times
went back to settings->system->developer options
toggled oem unlocking
enter pin
toggled usb debugging
hit always allow checkbox and ok on popup for authorization
adb reboot fastboot in my terminal
had to go to English Advanced then Reboot to fastboot on my phone using vol down and power
fastboot flash cust-unlock unlock_code.bin <~from the same directory where I stored the unlock code i got from OnePlus. (I contacted the FCC to get my metro phone network-unlocked, then contacted OP for the code.)
fastboot oem unlocking
hit volume down twice and power to unlock bootloader
it reboots itself to the OS after wiping everything...
back to step 1 so...
>after initial android setup having selected mobile data instead of wifi, skipping google account setup, and >entering a pin... basically and as soon as it would allow me to, i swipe down from top and use the gear icon to >enter settings.
>settings->about phone
>accessed developer options by tapping build number 7 times
>went back to settings->system->developer options
(oem unlocking should be greyed out because the bootloader is already unlocked)
>toggled usb debugging
> hit always allow checkbox and ok on popup for authorization
>adb reboot fastboot in my terminal
>had to go to English Advanced then Reboot to fastboot on my phone using vol down and power
then in my terminal
fastboot flash recovery DerpFest-11-Recovery-billie-20211023.img
fastboot reboot recovery
go to 'apply update'->'apply from adb' on my phone then back to terminal
adb sideload Derpfest-11-Community-billie-2021023.zip
wait like 10 minuites... it takes a good long while.
my terminal never goes past 47% for some reason and I always get 'adb: failed to read command: Success' when its finished
on my phone i used vol up and power to go back to the initial recovery screen
again went to apply update->apply from adb then back to terminal
adb sideload copy-partitions-20210323_1922.zip
hit vol down and power to select yes when it says signature verification failed
when it finishes and says OK i hit vol up to go back
then down to Factory Reset->Factory Reset->Format Data/Factory Reset
then reboot and
voila derpfest!