OK, so I've been playing around a bit. I now have three separate firmware versions on my player, one on disk, one flashed to RAM and one flashed to ROM.
I can run them all separately, using the bootloader menu functionality although, as expected, some things do not work due to version incompatibilities (codec failure, missing settings files etc.)
1. So are they there permanently now? No way of freeing up any of that space? (I didn't fully follow your answer to my previous Q4, how would removing the RAM copy free up ROM space?)
2. Can I use this functionality to keep maybe a known good firmware version in ROM, whilst regularly using and updating the RAM version?
3. I still think the Wiki is perhaps over-cautious when describing how to do a regular update. Am I correct in thinking that provided the updated disk copy of the firmware (ie current build downloaded from the Rockbox site) is run/loaded somehow (either RoLo or booting from disk) then it will be active and can be safely flashed?