Current u-boot version cannot handle correctly ext4 formated with 64bit
option, which is enabled by default with recent versions of mkfs.ext4.
If option 64bit is enabled, u-boot reads the filesystem erroneously,
listing wrong directories or displaying some directories such as /boot
as empty, which forbids itself from loading the kernel and failing to
boot.
See #3733 and https://github.com/armbian/build/issues/279 for more
details.
Pau Espin