CFW can be temporary as well, once you install a CFW you can go right back to stock no problems. Then there is no need for a dongle and if you want to go back to OFW you can. There is lower compatibility IMO using 3.41, finding hacked eboots and replacing them for all the games in the last 4 months is a pain in the arse. Or if you really want to stick to 3.41 you can do Hermes 3.41 CFW or make your own for what ever FW you choose using MFW Builder. There is just no need for a dongle and they are a lot more trouble then they are worth.
PS3 CECH-2501A [CFW] & CECH-3001 [OFW]/ PS2 SCPH-3901 & SCPH-7501/ PS1 SCPH-5501
Mod Cobra 4.46 v7.00 w/ E3 Flasher [CFW] & Cobra ODE 4.50 [OFW]/ Mod HDD-OSD [Phat] & Modbo 4.0 [Slim]/ Mod MM3
HDD 1tb [CFW] & 640gb [OFW]/ HDD 640gb & OPL v0.92 w/ 1.5tb SMB