Using /dev/ttyS0 under read-only rootfs

I have successfully created a read-only FS with the latest debian (2015-03-01) image and figured out how to get a USB drive mounted as well as the network running, however I can’t figure out how to use the UARTS, specifically /dev/ttyS0. I assume that the fact that the system is read only is the problem but I am not sure how I can “mount” the tty as read-write. Does anyone have any suggestions?

For reference my fstab looks like this:

/etc/fstab: static file system information.

You might want to mount your /dev as a tmpfs? A quick google gave me this:


I tried that, thanks, but it didn’t work. Maybe I didn’t have the syntax correct. Can anyone suggest the correct syntax?

After reading many articles I have made the USB drive and networking function but I really can’t find any information specific to this problem.


Correction. I should have said /dev/ttyS1 above not S0.