Can't seem to make bootable install USB

Try 'status=progress' with dd (without quotes).

From 'man dd':
status=LEVEL
The LEVEL of information to print to stderr; 'none' suppresses
everything but error messages, 'noxfer' suppresses the final
transfer statistics, 'progress' shows periodic transfer statis‐
tics

https://www.reddit.com/r/linux/comments/40c2km/did_you_know_about_dds_builtin_progress/

##EDIT##

I can't reproduce your errors/behaviour. Everything works as intended.

I tried Startup Disk creator on Trisquel 8; it works. Also tried dd -- works, although can't make it show progress (that's funny; status=progress is blank).

Suggestion: Gnome Disks is a fine utility that can restore disk images.

sudo apt install gnome-disk-utility

Install, right click on ISO, select 'open with' --> Disk Image Writer.

If you still can't write your ISO, check the USB drive, try with another.

Let's try in the terminal?

type

sudo -s

then

cat /directory/trisquelmini.iso > /dev/sdb

When "/dev/sdb" is your pen drive, be sure about this. Only work if you use "sudo -s".

Thanks for all the great suggestions. loldier's comment about trying a different USB port made me realize that I had also had problems moving a file with this port, so I tried a different port with Startup Disk Creator and it worked smoothly. So it's just a wonky USB port.

Thanks again!