05.15.04

X-Gold 608 firmware supplied with iOS 4.2b3 through 4.2.1.

Exploits

 * No exploit compatible with this modem firmware has been publicly released.
 * It is possible to upgrade the modem firmware to the exploitable 06.15.00, however this action will result in serious side-effects that can't currently be fixed as a baseband downgrade is actively blocked by BBUpdaterExtreme. More info