Looks like you have old firmware, type in: 192.168.1.223:8000/Flashmega to update it. Current version is 1.41 or 1.53
Everything is good on my setup, I'm always scared to upgrade, what exactly has been improved going from 1.41 or 1.53.
Any efficiency or notable performance improvements?
I upgraded from 1.41 -> 1.53 and put the setting on smart (1)... A notbale loss off GH/S @300MHz. Did around 915GH/S before and after those changes went down to only 800GH/s @ 300MHz...
Can the firmware be rolled back and how?
Take it off smart mode and it will use the 1.41 firmware.
Smart mode dropped me down to about 92% from a constant ~105% @ 300 Mhz. Using the 1.41 firmware I can no longer use 300 Mhz or it will result in 100% hardware errors on at least one board however 290 Mhz now yields ~116% efficiency so less electricity and more GH/s.

Stats:
Real performance:3111.11GHs, Expected performance:2672.64GHs, Utility:43461.37 Miner:116.41%
This is constant across all 32 of my boards running in a 50F-80F environment. Hope it helps.