[U-Boot] Pine64 problems with GPT partitions

Hi Andre,

You are the maintainer of Pine64 in U-Boot, so I want to let you know that Pine64 has problems to access GPT partitions, whereas MBR partitions seem to be OK.

There is a bug report from openSUSE here with additional informations: https://bugzilla.opensuse.org/show_bug.cgi?id=1098550

Guillaume