Variety of issues with iPod 5.5 (possibly hardware?)

[Classic55rock]

The strange one is the battery drain, as it is near zero in Apple Firmware, but high in Rockbox.

I may be a bit late but, if your classic 5.5 has a flash drive this is the source of the drain problem : disk start and stop events are not working as the hard drive ones.
There are a few patches for it and here are two of these you can try :
https://drive.google.com/drive/folders/1wKdyqGz5ofI_1yA80aYPaehHt54YW70h?usp=sharing

The folder includes the 2 raw patches and also builded versions of each.

[bobba_mosfet]

If I have an msata mod which works 100% perfectly without these patches, am I gaining anything by applying them?

Thanks in advance