codename: grouper / tilapia

git clone https://gitlab.com/Alpine-Mobile/pmbootstrap.git
cd pmbootstrap
./pmbootstrap.py init
./pmbootstrap flasher flash_kernel
./pmbootstrap export

# start TWRP
(computer) $ adb shell
(twrp) $ df # look for the data partition. should be something like /dev/block/mmcblk0p9 or p10 with /data next to it
(twrp) $ umount /dev/block/mmcblk0p__ <- fill partition number
(twrp) $ umount /dev/block/mmcblk0p__ <- fill partition number # again, it can be mounted as /sdcard and as /data
(computer again) $ adb push /tmp/postmarketOS-export/asus-grouper.img /dev/block/mmcblk0p__ <- fill partition number

• grouper has likely data on /dev/block/mmcblk0p9 but make sure!
• tilapia has likely data on /dev/block/mmcblk0p10 but make sure!

it's probably because tilapia has additional modem partition. If you're not sure, come to our Matrix channel and ask :)