3.55 requires no dongle, to jailbreak.
this is tut i found on ngu and its this bit (4. usb downgrade dongle - Check here to see options for a downgrade dongle. ) that i am talking about as i am new to jailbraking and 3.55
1. PS3 compatible with e3 flasher. Any nor chip model PS3. Except those that came with a higher firmware than 3.55 from the factory.
2. an e3 flasher
3. micro sd card formatted to fat32 (I recommend to use a 2gb or less Sandisc. Just a recommendation and others may work fine.)
4. usb downgrade dongle - Check here to see options for a downgrade dongle.
5. usb flash drive formatted to fat32
6. Download the Downgrade any file pack
7. Patience, common sense, and the ability to follow directions.