PIX 515E - Downgrade from 7.0 to 5.29 Mayhem

Tricky. The first version of PIX OS that supported the 515E at all was PIX 5.2(7), just two subreleases before the version you are attempting to test. And in PIX 5 and PIX 6, the maximum RAM permitted on the 515E is 64 Kb.

Have you tried "flashfs" first ? PIX 5 used a different flash file system directory organization.

Using "flashfs" is tricky: as best I can tell, after using it you next have to drop down to the monitor mode. If you save your configuration or if you reboot even once before going into the monitor, then PIX OS will restore the old flashfs directory structure.

I don't know; I've seen conflicting reports on that point. It appears to vary according to how far back you are going.

Looks like the appropriate command is "downgrade":

That looks to me like something related to RAM size.

Yep that's the command you need to use, flashfs has been modified, any attempt to flash with an old binary is hazardous.

You'll have to downgrade to 6.3 or 6.2 and then flash with 5.29 firmware. (I think so)

You might have to load 6.2 first.