I'm not quite sure it's related. I have the same /system mount issues with both daboss and alexandr's version of DevBase.
Any Pie ROM installs just fine, a backup of this ROM also gives the same error however flashing system image separately let's it boot even with /system wiped before that and NOT flashing system backup.
The only way I can flashing either of these ROMs is to Odin ARL4 onto my phone and flash it without wiping. This will.give the /system but the Odin flashing already put /system on the phone so it just boots.. I can Imagine extracting the system.img from the ROM zip and fastboot flashing it should work just fine.
Any Pie ROM installs just fine, a backup of this ROM also gives the same error however flashing system image separately let's it boot even with /system wiped before that and NOT flashing system backup.
The only way I can flashing either of these ROMs is to Odin ARL4 onto my phone and flash it without wiping. This will.give the /system but the Odin flashing already put /system on the phone so it just boots.. I can Imagine extracting the system.img from the ROM zip and fastboot flashing it should work just fine.
