I accidentally formatted my Android phone's storage partition while updating to Android Oreo today. When I tried to restore the backup I realized that the backup of the data partition had failed and basically is an empty file with 0 Bytes.
I would like to run PhotoRec over it but I'm somehow unable to get my phone into mass storage mode. It seams like Google has ditched it for MTP. I tried some apps from XDA but none of them really worked with my device. I was able to get the external SD mounted but not the internal storage. The custom recoveries that are available for my device only support MTP as well.
Does anyone have an idea how it could be possible to recover my files? I'm rooted and bootloader is unlocked.