Team Cobra has finally announced the update to their USB which allows support for 3.55 and more. You will need their MFW to use Cobra features on 3.55. they have also discontinued support for 3.41.
Team Cobra’s Announcement about the update:
The Cobra Team is proud to present the Cobra 3.0 firmware pack, available from downloads section. In this release we enabled the Cobra USB device on 3.55 via use of our own cfw. Enjoy the release and look forward to many new features to come in future releases. Please be sure to read the updated user manual for detailed instructions on upgrading and usage!

Cobra USB Changelog:
- Added compatibility with 3.55. Support for firmware 3.41 is discontinued, since now all updates will be for 3.55.
In 3.55, Cobra keeps all the features of previous versions, adds the ones listed below and also removes some of the annoyances of the jailbreak exploit.
Please, follow the steps in the manual, you must install first Cobra 3.55 cfw.
- Added a new discless mode for PS3 backups in jailbreak format. This mode will be activated automatically when you load a backup and there is no disc inserted.
In this mode, games are loaded from disc icon, not app_home, although app_home hack is still supported.
This mode has a higher compatibility than the app_home hack, and smaller than discless PS3 isos.
- Added support for PS2 backups in iso format to the remaining backwards compatible models (CECHA and CECHB).
- PS2 isos can now be played discless too.
- Fixed compatibility issue with GT5. If you still experience problems, please delete installed game data from XMB and try again.
Source via Cobra USB
**You can find Cobra Manager, Cobra USB firmware update, and their MFW in the download section on their site
Update from Andrea1Liquid: By reading the user manual we can tell that how we expected the 3.55 pack to work was correct. You have to update Cobra to the latest firmware, update your PS3 to Cobra’s 3.55, then switch it off (no full power off required). Insert your Cobra USB Dongle in PC mode and power on the PS3. Basically, the dongle will work as an authenticator the firmware will check in order to enable the custom features of Cobra’s 3.55. Check the user manual for the detailed instructions