Good that you have it working to this point, though.
I think the root file system is corrupted (due to not properly unmounting or re-mounting it read-only).
The way to go is
- you've got to get yourself a partition image of /dev/mmcblk0p1 (first partition on the flash disk), maybe a kind soul can provide it to you,
- you've got to dump it to the first partition of your device's flash disk.
When doing the latter (via option 3), you will find that there's a passwort that needs to be entered. I'm not sure, but I think you need to recover it from the Serial No of your Kindle. Maybe others can comment on this.
The whole procedure is showed in a video that seaniko7 made:
https://www.mobileread.com/forums/sho...d.php?t=134637
The mkfs is not needed, since you're dumping a full partition image anyway. The hardest part will probably be to find out the password for your device.
In the recovery menu, do NOT chose 4 (Erase MMC0) and probably not the format option either.
I'm not sure about books and stuff. I think you will probably need a (live CD/usb stick?) Linux, although you probably can dump partition images on windows, too. Someone with expertise in that regard might jump in here...