*2767*3855# - FULL E2P RESET
*2767*2878# - CUSTOM E2P RESET
#*7337# - UNLOCK
*2767*688# - UNLOCK
*#0523# - CONTRAST
*#9998*523# - CONTRAST
*#8999*8378# - Service Menu (X100)

*#06# Show IMEI
*#9999# Show Software Version
*#0837# Show Software Version (instructions)
*#0001# Show Serial Parameters
*#9125# Activates the smiley when charging
*#0523# LCD Contrast

*#9998*228# Battery status (capacity, voltage, temperature)
*#9998*246# Program status
*#9998*289# Change Alarm Buzzer Frequency
*#9998*324# Debug Screens
*#9998*364# Watchdog
*#9998*377# EEPROM Error Stack - Use side keys to select values
*#9998*427# Trace Watchdog
*#9998*523# Change LCD contrast
*#9998*544# Jig detect
*#9998*636# Memory status
*#9998*746# SIM File Size
*#9998*778# SIM Service Table
*#9998*785# RTK (Run Time Kernel) errors - if ok then phn is reset,
info is put in memory error
*#9998*786# Run, Last UP, Last DOWN
*#9998*837# Software Version
*#9998*842# Test Vibrator - Flash the screenlight during 10 sec
and vibration activated
*#9998*862# Vocoder Reg - Normal, Earphone or Carkit
*#9998*872# Diag
*#9998*947# Reset On Fatal Error

и вот здесь неплохая подборка кодов http://yasikgsm.narod.ru/