ok, here is a list of all the codes for the xbox(the original; not 360):

these codes will appear at the top corner of the screen, some problems will not show this. If you get an error it will show at the top corner and say: "error, please contact customer support" or something like that. I will do my best to cover all errors.

1 - bootldr - Unknown exactly, something to do with checking the motherboard(not sure how to fix, maybe a burnt trace)

2 - bootldr - Eeprom check failed(not sure, maybe deleted or no eemprom)

3 - bootldr - not used

4 - bootldr - Ram check failed(no ram?)

5 - kernel - HDD not locked (retail bioses require the hd to be locked)

to fix this you will need to take apart your xbox and replace the hdd.(you can buy stock hdd's at llamma.com in the xbox page)

6 - kernel - Cannot unlock HDD(hdd is locked and cant be unlocked, so you'll need to buy a new one)

7 - kernel - HDD timeout

8 - kernel - No HDD found(no hdd in xbox, meaning you most likely pulled it out)

9 - kernel - HDD parameters (PIO/DMA/or size {debug}, certain size minimum is required for debug)

10 - kernel - DVD timeout(cant read disk or disk read error, buy a new dvd drive from llamma.com and replace it)

11 - kernel - No DVD Found(no dvd in drive, or drive problems(buy a new one)

12 - kernel - DVD parameters (PIO/DMA)- not sure how to fix this

13 - kernel - Dashboard launch fail (due to missing/bad key, or anything else that would prevent it from running) and the dashboard didn't specify why it failed.

14 - dashboard - Error loading dashboard (dashboard generic error)

15 - - not used

16 - dashboard - Other files to do with dashboard / dashboard settings (specific dashboard error)

17 - - not used

18 - - not used

19 - - not used

20 - kernel - The dashboard was attempted to load and failed; It was a cold boot, and the dashboard didn't specify why it failed, but it (for some reason) needed to be noted that the dvd passed the challenge/response authentication

21 - anywhere - This error says that the machine was booted to display a error, basically someone told the machine to reboot (or launch a xbe) with this flag, and the error code just means its been rebooted by the flag