Here is some gingerbread codes, maybe you dont know:
*#*#0*#*#* screen test menu
*#0011# network mode/cell info/power info hidden menu
*#*#4636#*#* for battery and other general setttings like GSM/CDMA
*#*#8255#*#* for Gtalk service monitor
*#*#7780#*#* for factory data reset
*#*#34971539#*#* for information about phone camera (be very careful hitting options here)
*#*#7594#*#* change the "Power" button action in your phone.
*#*#197328640#*#* service mode
*#197238640# service mode
*#0*# testing mode
*#1234# display phones current firmware
*#*#1472365#*#* gps test (work on 2.2)
*#0011# network mode/cell info/power info
*#*#0*#*#* screen test menu
*#7465625# engineering mode
*#3214789650# gps service menu for JP3 fw
*#9900# Sysdump screen.. way to dump ram and other logs to sd card
*2767*3855# FACTORY DATA WIPE AND internal SD RESET as soon as you enter # use only if you want wipe your phone
*#*#273283*255*663282*#*#* Opens a File copy screen where you can backup your media files
*#*#3214789650#*#* - GpsSetup2
*#7284# - UART and USB options
*#1234# - Version
*#06# - view IMEI number
*#*#4636#*#* - usage stats and device info
*#9090# - service mode UART and USB /slightly different form the 7284 one/
*#9900# - sysdump /if you dont know what it means, probably you won't need this one /
*#03# - NAND flash unique number
*2767*3855# - hard reset
*#*#7780#*#* - factory data reset
*#0*# - testing mode
*#*#4636#*#* - Usage stats and device ingo
*#0782# - Real Time Clock
*#0011# - GSM status
*#*#197328640#*#* - Servicemode, Debug, Netz