Some people may not know that the HTC its many hidden menu or feature, here I want to share it few:
1. Secret code
*#*#4636#*#*
It will bring up a testing menu with a few interesting bits and pieces about what's using the CPU and the battery.
2. Screen Capture
For HTC Desire HD version to 2.3.5 it can screen capture by holding power button and tapping the home key
3. Power saving tips:
Don't use a live theme
Use a dark wallpaper
Turn off wi-fi & bluetooth when not in use
Stop friendstream, facebook & peep updating every 5mins. Set mine to manual.
Set email app to manual
Set screen brightness to auto or 40% (lower if you can put up with it).
4. Running applications tip
Press and hold the home button. You will see the six last active applications for you to easily switch back to. Can be handy if you have to go through to another home screen just to go back to what you were doing before.
5. Adding New Ringtones/SMS Notifications/Alarms
To add new ringtones or SMS alerts, connect your Desire to USB and mount the device on your PC. Browser to the following folders:
Ringtones: /sdcard/media/audio/ringtones
SMS Alerts: /sdcard/media/audio/notifications
Alarm Alerts: /sdcard/media/audio/alarms
Copy your mp3 files into either of the folders above. Then go to:
Ringtone:Settings -> sound and display -> phone ringtone
SMS: Settings -> sound and display -> notification sound
Alarms: Set the sound when adding a new alarm.
Then select the ringtone you put in the above folder.
6. Download and save YouTube videos
Online videos are great. You can view them from just about anywhere, and much of the time, they're absolutely free. But at times, especially while on the go, connectivity can be a barrier between you and the video you want to see. When coverage-related issues arise, it's just handier to have the videos you want to watch stored right there on your memory card. If you have an HTC Desire HD, achieving this couldn't be easier with YouTube videos.
In this guide, we show you how to locate the video you want and download it directly to you handset.
- Navigate your phone's browser to the YouTube video you want to download
- Click on the video's URL and use the Android Web browser to open it rather than the YouTube application
- While in the browser, hit Menu and then Go To URL, Here's where the magic happens.
- The video's URL should be in the URL field. Place your cursor directly after the "www." and type in the word "pwn" before "youtube.com"
- The resulting link should look something like "http://www.pwnyoutube.com/videocode"
- Hit Enter
- Simply tapping the Download High Quality MP4 Video option on this page will download the MP4 file directly to your SD card
Now you have the video you wanted stored on your device for viewing whenever you want, whether or not you have wireless coverage.
7. Manual full wipe
Open ROM manager_tap reboot into recovery_loading_clockworkmod
Wipe data
Wipe cache partition
Advanced_Wipe dalvik cache
Instal ROM from sdcard
Flashing ROM
FAQ
Root, what is it?
Root is like getting superuser permissions. So, there are some applications that require permissions, especially for the ROOT application, that is why Root is the beginning of all your modding.
* Warning * if you do a root mean your warranty is charred, most likely after the Unroot be back guarantee, but no one has tried to check the warranty after Unroot to date
Custom ROM, what is it?
ROM (Read Only Memory) is where to store the files on your OS (DHD = Android). while the Custom ROM is a function of the basic program functions that exist in the ROM that has been altered appearance by a party to a third of developers
Radio, what is it? Flashing the radio was worth anything?
Radio in this case that relate to your signal (edge, hsdpa, 3g). Radio flashing point to improve the performance of your signal because in a few custom ROM Radio that there may be less than the maximum that should be replaced with the recommended
How to install applications that are downloaded from a PC?
If the file downloaded in the form. Apk please immediately installed directly on the DHD (Must have a file manager ex Applications: AndroZip, Astro) or via HTC Sync. If the form. Zip please extract it first and install the file. Apk
GPS Lock folder to long?
Please download FasterFix and GPS test plus the android market.
* Caution * GPS on DHD try to Lock when visible sky, if inside the building will usually be longer to Lock.
When opening the application appear like this Warning: the application xxxx (process com.htc.xxxx) has stopped unexpectly. please try again, force close?
your application indicates that there is a crash or anything so it can not open it. If the "xxxx" is a program that emerged from HTC STOCK please Go into Settings> Applications> Manage Applications> Search applications> tap Clear Data. If the "xxxx" which appears in the application that installed itself please reinstall
SDCARD you are not readable when mode Disk Drive?
Please check back with great for your memory card is installed properly or not. If you can not also please mount sdcard - unmount sdcard - mountsd card (in CWM, only to have ROOT)
When performing Root, DHD stuck?
please check your build number DHD, DHD likely you -> 1.72 or Branded DHD (T-mobile, etc.)
How to check the build number?
Setting -> About phone -> Software Information
Battery DHD wasteful?
Battery for Android will not hold more than 1 day. For normal use may only until tonight. If very intensive probably only until the afternoon even noon. Do not Wonder
Reboot and loading application takes a long time?
for those of you who have installed many applications may be a little feel. advised to upgrade your sdcard into Class 6 / 10.
ROM of the most stable at this time?
For now possible: LeeDroid and ARHD
flash the ROM, needed Full Wipe?
Yes, for Flashing ROMs is highly recommended for Full wipe data, wipe Cache Full. If you flash the ROM from a developer (eg Leedroid v2.2.2 to v2.2.3) then wipe the cache does not have to. but if another developer (eg LeeDroid want to ARHD) then it is highly advisable to wipe the data and cache
Flashing should radio?
Once again it is OPTIONAL Flashing Radio. if after you flash a custom rom and your signal either "then you are not flashing just the radio do not do anything. But I remind each developer had to include the Recommended Radio ROM for the developer. Logically, Makes it suggested it means there will be an increase in performance if we follow the suggested radio.
Root, custom rom, flash the radio, etc. causes the brick?
Flashing the radio when there is a warning if it fails to be brick. But so far no one has been experiencing BRICK, but always keep in mind
** DO IT WITH YOUR OWN RISK **.
DHD Brick?
until now there has been no tutorials Brick for brick overcome.
Some malicious programs/malware try to hit the Android OS is higher popularity. Here are some of the most famous Android malware detected so far, reported by InformationWeek: 
