Thanks for all the work. This is an error report.
I hooked up an external USB hard drive with its own power supply (which has been working in another computer.) After I got the newest kernel and uEnv using scripts, and rebooted, I used the script to install the MATE GUI. When the script finished, but before I rebooted, I tried to copy (using cp) around 900 MB in around 1000 files from /var/cache/apt/archives to the hard drive. (/dev/sda2 mounted on /media/ubuntu/sea2/) I got many error reports. It turned out something like 200MB was copied and a lot of the files had only their names copied but the file sizes were 0. These are some of the errors, but the others were similar.
usb 1-1: device descriptor read/all, error -71
Call trace:
INFO: task jbd2/sda2-8:22773 blocked for more than 120 seconds
Call trace:
INFO: task ext4lazyinit:22775 blocked for more than 120 seconds
When I tried again, it said there was no such directory as /media/ubuntu/sea2/, but if you umount and mount, the directory is still there. So you can repeat the process, but the same thing happens again.
Rebooting and attempting the same thing from the GUI, gave the same results. That is, files seem to be copied, but only a few hundred megabytes in total were copied; a lot of files were 0 bytes; and then the destination was reported as not existing; but you could get the directory back by umount and mount again.
Well most certainly you suffer from undervoltage and your Drive just shuts down.
Maybe your pine64 power supply is marginal and causing usb transceivers to be flakey ?