@Leeful no worries, thanks for the detailed steps!
Unfortunately I have an issue with the trophies (haven't tested the savedata yet, I have to reinstall everything).
After I restored everything and rebooted, I can see I have 170 trophies when I hover the "trophies" icon. But if I select it, it prints "CE-30360-2" error, and when I hover it again, everything was deleted, do you have an idea?
I checked a tutorial for the 5.05, it says to save addcont.db, app.db and av_content_bg.db from system_data/priv/mms, should I try the same?
Edit: I reinstalled my Tekken 7 copy; when the game tries to load my save, after a while it warns "save corrupted, it will be deleted", I guess it's also not working...
When I did the backup on my 7.55 I unticked "applications" to save time, should I redo it and include them?