I recently updated my GPD XD Plus to Lineage OS 18.1/Android 11 and everything went smoothly with the device behaving as expected. I then wanted to try downgrading to Lineage OS 16.1/Android 9 to see if performance was any better and that's when the issue started.

I updated my GPD XD Plus like normal using the SPFlash method and am now experiencing an issue entirely new to me. The GPD when powered on won't load past the animated boot logo.

I've since tried several different revisions thinking maybe it was just that version, but Lineage OS versions 15.1/16.1/17.1 and even going back to 18.1 all now produce the same issue. I even tried downgrading to various CleanROM versions and even then it still hangs on the Android boot logo.

I've formatted the device in SPFlash, Wiped/Formatted everything in TWRP and have tried flashing the device (which always succeeds without error) over twenty times now but the story is always the same, it won't load past the animated boot logo. At least I can still access Recovery.

Does anyone have any idea what could be causing this? I've exhausted Google searches and couldn't find anything specific to this particular problem, thought maybe someone here would have an idea what could be causing it or how to get it resolved. I'd appreciate any input.