Error codes
General Information
E64: Unknown
E66: The key of the DVD drive firmware doesn't match the key of the motherboard.
E68: HDD Failed to initialize.
E74: According to Dennis Mooney (Xbox ATG) on the 360 dev forums E 74 is HSIO Calibration failed. (HSIO is that insanely fast bus between the EDRAM and the Xenos core. It needs to be "trained" to be reliable.)
E79: Unknown
Confirmed facts
When the Xbox crashes half way loading a game disc (e.g. Due to bad unreadable sectors half way)
- It halts itself to a freeze: The Screen which was active, remains.
- Eject does not do anything
- USB Devices are no longer working
- Wireless Controller does not connect
- Plugging in a USB Controler only lights up Left Corner, and Right Down Corner
- Unconnected Video Out Cable results in red flash, Reconnecting removes red light
- The only way to get your box back is to unplug the power cable
Speculation
Error 79 has been known during obvious signs of graphic corruption. (Overheating?, Power supply insufficient?)
- Error 79 can occur if the Xbox 360 firmware is corrupt.
- Error 74 can be fixed by disconnecting and reconnecting the hard drive. This would be in contrast to the Dennis-Mooney-Quote.