Got a solution for this problem! After I saw this post: Free (small) partition for storing serial number? - #15 by sierra-wireless I thought about formatting the userapp MTD16 partition and splitting it into two UBI volumes (the first gets a quarter of the space and is the original userapp (the one that gets mounted to /mnt/flash) and then the second one gets all the remaining space and gets mounted as RO in another place, where I put the scripts and the machine monitoring setup). Doing this I’ve yet to have a problem, and in case something happens to the /mnt/flash, I’ve got a restore procedure that fixes it. Pretty elegant, and it was very easy to do (another 20 lines in S02mount_early). Can’t give much more detail tho.