USB Mass Storage mode broken with empty GPT

[lukaslihotzki]

With pine64-pinephonePro-2023.07-007 and an empty GPT on eMMC, the USB mass storage mode reboots immediately when entered with volume-up, even without connecting it to a host.

The empty GPT can be created with the fdisk commands "g⏎w⏎". Booting from SD card with volume-down still works, so use that to erase the empty GPT with dd if=/dev/zero of=/dev/mmcblk2 bs=32M count=1, for example. Then, the mass storage mode works again.