[SOLVED] Mounting USB EXT4 Partition Fails

[Nachteule]

There is one ext4 patch commited Jul 9 which may be responsible for your issue

So the question is, what was your kernel version before 4.14.58+? Kernel 4.14.52+ (built Jul 2) is still available for download, but that makes no difference: seems your fs on sda1 is broken and needs to be fixed (but unfortunately don't know how to do it, you could play with -f and -b option when running e2fsck)