[Desire HD Q&A, Help & Troubleshooting] eresen:
From http://mobilecon.info/htc-secret-code.html

Please Use the code wisely, some code have an effect that cannot to restored

HTC secret Code

Tested/Working Code:

##775# – EPST/PRL – PRL Settings

##786# – EPST – Status Menu

##3282# – EPST – Data Programming Menu (User Name, Advanced, Restore, Enable HFA, DSA Server, MMSC URL)

##2539# – EPST/A-Key – Data A key menu

##7738# – EPST/P_Rev – Protocol Revision

##8626337# – EPST/Vocoder – Unsure

##33284# – Debug – Debug Menu – (Debug Screen, Test Calls, RC Data, HDR/1X Selection, Voice Privacy, DTMF Set, Korea Mode Set)

##3424# – Diagnostic – Connect to phone in diag mode

##4772579# – Reset the GPS

##72786# – changes DSA back to Factory

##889# – enables TTY

*#*#34971539#*#* – update firmwire

*#*#7594#*#* – change the End Call / Power button action

*#*#273283*255*663282*#*#* – code opens a File copy screen where you can backup your media files

*#*#197328640#*#* – enter into Service mode

*#*#232339#*#* – WLAN test (Use “Menu” button to start various tests)

*#*#526#*#* – WLAN test (Use “Menu” button to start various tests)

*#*#528#*#* – WLAN test (Use “Menu” button to start various tests)

*#*#7780#*#* – Factory reset

*2767*3855# – Factory Format

*#*#232338#*#* – Shows WiFi MAC address

*#*#1472365#*#* – GPS test

*#*#1575#*#* – Another GPS test

*#*#232331#*#* – Bluetooth test

*#*#232337#*# – Shows Bluetooth device address

*#*#8255#*#* – launch GTalk Service Monitor.

*#*#4986*2650468#*#* – PDA, Phone, H/W, RFCallDate

*#*#1234#*#* – PDA and Phone

*#*#1111#*#* – FTA SW Version

*#*#2222#*#* – FTA HW Version

*#*#44336#*#* – PDA, Phone, CSC, Build Time, Changelist number

*#*#0283#*#* – Packet Loopback

*#*#0*#*#* – LCD test

*#*#0673#*#* OR *#*#0289#*#* – Melody test

*#*#0842#*#* – Device test (Vibration test and BackLight test)

*#*#2663#*#* – Touch screen version

*#*#2664#*#* – Touch screen test

*#*#0588#*#* – Proximity sensor test

*#*#3264#*#* – RAM version

—– Was only able to get the following working on CM6 Rom —–

*#*#4636#*#* – Phone Information – “Phone information, Battery information, Battery history, Useage statistics, Wifi information” (froyo only)

Confirmed not Working:

##UPST# – modem directory

##778# – EPST – Advanced Programming

Unverified code:

##37872# – Full Speed USB Mode – Enable/Disable

##3386# – DDTM – Enable/Disable

*#0011# Service menu

*#0228# Battery Status

*#2454# Low Battery Power Off

*#0283# Receiver Packet loopback

*#0782# RTCTimeRead displays time (and seconds)

*#147852# Allows you to access many screens including CDMA DATA Connections

*#369852# Allows you to access many screens including CDMA DATA Connections

*#1472365# GPS Setup

*#232331# Bluetooth RF Test Mode

*#1575# Service menu

*#197328640# Service menu

*#2767*2878# Service menu

*#32489# Service menu

*#4238378# Service menu

*#6984125*# Service menu

*#7284# Service menu

*#9090# Service menu

*#2580# Service menu

*#2664# Touchscreen Firmware Version

*#2664# Main Firmware Update

*#3264# RAM Version

*#3282*727336*# Current Data State

*#745# Sec_RIL_Dump allows you to copy to phone memory, clear ril log, (greyed out copy to SDcard and view RIL log), exit

*#7450# Phone Dump Mode Disable

*#7451# Phone Dump Mode Enable

*#7780# Factory Reset

*#9900# SysDump copy logcat/dumpstate/dumpsys, enable debug log, copy watchdogdumpstatelog)

*#0*# – Test Utility – SAFE TO PLAY WITH

*#0289# Melody Test again?

*#0673# Melody Test SAFE TO PLAY WITH

*#0842# Vibration test SAFE TO PLAY WITH

*#2263# ??

*#2663# Touchscreen Accuracy Test SAFE TO PLAY WITH

*#767*3855# Factory Format – CRAP!! WARNING!!!

Use the code wisely, some code have an effect that cannot to restore

- See more at: http://mobilecon.info/htc-secret-code.html#sthash.SQkVC8dW.dpuf