/dev/sdb read-only filesystem

Solution 1:

Let us point out one set of facts...

The easy way to "fix" a troublesome device, assuming the content doesn't matter:

1. boot from any other device.
2. do NOT mount anything from the trouble device
3. Convince yourself to be 100% sure you're working with the CORRECT /dev/name,
   using lsblk and pondering on it's output might be enough.
4. Start a terminal / bash and type
   sudo dd if=/dev/zero bs=1M count=1 /dev/name at the prompt
   Re-Read what you typed at least twice,
   only when you're entrirely sure it is the correct device - press ENTER

This should work, ... assuming that there is no hardware problem (failing flash-based device, or HDD with IO or surface problems).