Extremely slow USB to USB transfer

[Jingles]

I just read your message wrong makes total sense and now feel slightly daft!

Anyway...

I added debug in cmdline.txt, rebooted and ran the commands. I have attached the log file. I have also attached the fdisk, and a hdparm with the -I option just in case.

I don't think the dmesg has the info you want though. When I ran the command I got a new line in terminal with a blinking cursor ( _ ), but it didn't come back to the normal prompt when it's ready for the next command (i.e. root@sierra #~), even when i left it overnight. I had to kill it with ^ C.

When I looked at the log it only has info for /dev/sda and it was still /dev/sdb that was reading slowly (see hdparm.log). NB the last five entries (resetting USB device) appeared after I ran the hdparm command.