Start the PS3 and install "Rogero CEX-3.55 CFW V3.7" using the System Update from XMB.
Once you're back on Rogero CFW3.55 v3.7 you can now install any CFW you want using the System Update from XMB (or Recovery Menu if XMB Update didn't work).
Stay tuned for more PS3 Hacks and PS3 CFW news, follow us on Twitter and be sure to drop by the PS3 Hacks and PS3 Custom Firmware Forums for the latest PlayStation 3 scene updates and homebrew releases!
I also have the same issue with a PS3 with no BD drive at all, running rogero 4.40 v1.03. So I have started to play with cloning my PS3's again, just for the games side I mean. (In a nutshell creating my games to PKG's installing them on a modded Ps3 then data transferring to the PS3 without the BD drive. It also works on an fully updated none modded PS3, with some games, which is nice. )