On the internal SD of my device I found this partitions:
/dev/sdb1 fat32 3,2GB
/dev/sdb2 fat16 32MB
/dev/sdb7 ext2 34,5MB
/dev/sdb8 ext2 244,5MB
/dev/sdb9 ext2 98MB
/dev/sdb10 ext2 cramfs 16MB
Boot partition is the Fat16 one, ergo: /dev/sdb2 fat16 32MB
Only this partition has to be mounted and manipulated.
Creating an image before, that can be copied back is a good idea. Howto is written somewhere here:
https://www.mobileread.com/forums/sh...d.php?t=278728