So after spending ages trying to recover my USB drive after it wouldn't work with the new 9.0 jailbreak. I've found a way to recover it. I think the exfathax.img file can corrupt it or rendering it unrecoverable. When plugged in to a laptop the USB wouldn't show up and if it does it can not be formatted. On rare occasions it may show a wrong volume size which in my case 16gb was showing as 64mb. Hope this helps someone.
Go to https://propakistani.pk/how-to/how-to-format-usb-in-cmd/ & follow the instructions under Formatting USB Flash Drive in CMD (Diskpart Command)
Go to https://propakistani.pk/how-to/how-to-format-usb-in-cmd/ & follow the instructions under Formatting USB Flash Drive in CMD (Diskpart Command)