(I have also asked on stackoverflow, as I assume the use of developer tools is neccessary, but I would be very glad to get any working help on here also.
The Google Photo App filled up the 16 GByte "Rom" of my Motorola G5: Google memory overview showed around 6.5 GByte of "Google Photo" data, whereas real (not deleted) photos and videos were only 4 GByte and I had moved those 4Gbyte to the SD card. To be on the save side before hitting "delete" of the 6.5 GByte, I removed the SD card beforehand. But now, when trying to restart, Android is stuck in the booting/start sequence. (I still can enter the pin, then the normal boot/start screen appears, but that only disappears shortly each 5 to 10 seconds. Stuck there.)
Question: Could I access in any way the "Rom" of the smartphone, so I could remove all or part of the 6.5 GByte occupied by "Google Photo", using for example adb?
I have Android 8.1 on the G5 and Win 10 on my computer.
readbackverify="false"
(experts only). for FBE you could then just delete some files. sadly your device uses FDE. the only (unrealistic) chance is to downgrade bootloader in order to make bootchain vulnerable, disable avb and flash twrp (which decryptes userdata). this will take several days for research. you can start with figuring out how to boot in EDL mode via test point – alecxs Jan 29 '20 at 11:22