Originally Posted by datunes
I wouldnt Believe this for a second i have tried many times using many different methods to get TBCFW V2 and OFW 4.11 to Dual Boot with absolutly no success. Dual boot is only possible while using TBCFW V1 which is not compatible with dongle update 2.7, dual boot is also possible when using some other CFW which are not compatible with the true blue dongle.
I can confirm its possible, i have a 120gb slim ps3 and had the same problem you had. The OFW mode (switch 2 down) with 4.2 wouldn't coexist with a working (green light) install of TB in CFW mode (switch 2 up). if i reinstalled 4.2 the TB dongle wouldnt go green. If I reinstalled TBCFW 3.55v2 upon switching to OFW mode it would ask me to reinstall.
The folks at electrolado came up with a counter intuitive solution which worked for me. You'd install TBCFW 3.55v2 on both CFW and OFW modes BUT you'd then upgrade the CFW bios (switch 2 up) to 4.2 instead of the OFW (switch 2 down). Weird I know, but it works. Could it be an issue for a small number of us with a certain model of ps3 and e3?
Some french folks also have this working but their tut didn't work for me. Theres a video at the bottom of the page showing them switching between 4.2 and TB with the dongle turning green.
So don't lose hope