The fifth beta of the untethered jailbreak for 4.2.1 has been released, and includes a fix for the Bluetooth issue that plagued users. The Dev-Team has also created a Windows version, but will not yet be releasing it due to “excruciatingly slow” speeds.
If you have legit access to the 4.2b3 IPSW, check it out. Requires a fresh restore.
[Dev-Team]