I have a first generation Google Pixel the bootloader of which is unlocked and is running stock Pie. I need to recover deleted files on it because a move operation got effed up by ES File Explorer with confusing dialogs. Performing file recovery requires root, but I don't want to install a custom ROM. Is there instead a way I can run one in RAM that is delivered to the device over USB?
Answer is too late but may be helpful for future visitors.
First of all, there are a number of factors which make data recovery impossible, particularly if you keep on using the device. See this answer for more details.
Secondly since you have an unlcked bootloader (but don't want to go with custom ROM), you can flash a custom recovery like TWRP (or boot directly from
fastboot) and from there dump your
/data partition to a PC using simply
dd command or USB Mass Storage (UMS). Then you can apply any data recovery techniques on the partition image e.g. recovering from
journal or by
carving through sectors.
For detailed steps: How to recover a deleted file from /data partition?