I have a system running on a 4GB Nandrive. When the drive is full, Ubuntu will not boot :( and I have to plug in a rescue thumbdrive to delete files. The problem is the hardware is not easily accessible except via network.

Is there a sure-fire way to boot Ubuntu, say, to RAM or other means when the disk is full or on any other errors in the normal boot process?

In other words, is there a fallback rescue boot mode with networking?

Thanks for any advice.