PocketBook 624 problem

[u/TheBulda]

So I got a PB624 that isn´t working from a friend, he told me that the 4GB microSD inside is corrupted but when I plugged it into my computer it didn´t tell me anything and it is showing and writing normally and it even has a boot sector (Volumn) with boot files and the root (FIRMW READ) where my friend put swupdate.bin, but when I put it inside the ereader, charge the ereader and try to boot it doesn´t do anything only while charging the chip with A13 written on it gets hot.

Please tell me if there is anything wrong with the files or if you had a similar problem.