SSR1300 running 7.0.1-1.r1 fails to downgrade to 6.2.6-15.sts. The user experience is that the downgrade is initiated, it takes a while for the download to happen, then it stays at upgrading 98% for about an hour. It appears to actually downgrade, showing upgrading 98% in mist, however logged in via the console it was on 6.2.6-15. Then something happens and it reboots back to the 7.0 code.

The downgrade process appears to work but then loads the old code on reboot.

Downgrade to 6.3.5 first, then subsequently downgrade to other lower versions.