One possible reason for a read-only filesystem is a set “dirty-bit”.
To change this the linux tool fsck can be used.
First the badge needs to be ejected safely, then it needs to be restartet and put back into “USB storage” mode.
The device should not be mounted. Now
lsblk can help with finding the correct blockdevice.
Then you can check the filesystem with
fsck /dev/sdX (replace
sdX with the correct device).
If neccessary the tool will ask if the “dirty bit” should be removed, this needs to be answered with yes.
After this, the problem should be solved.
If operating does not show a file system after activating USB Storage Mode and attaching it via USB, a few things might be at fault: