The first thing I have to point out here, this is a VERY dangerous thing to attempt.

Before you read on, I want you to take 2 minutes to imagine a worst case scenario that you are turning your beloved Desire HD on and nothing is happening.  Instead of the loverly white screen and HTC logo with annoying ‘budum da dum dum’ noise you’re looking at a blank, dark, black, lifeless screen…

Do you -

a) cry uncontrollably, open the window if your 3rd story bedroom and launch yourself out

b) reach for the razorblade carelessly left on your computer desk and slide the blade over your wrists and wait for the end

c) toss it aside and pick up your back up phone, not caring for the loss of your £450 device

If you answered a) or b) then this really isn’t something you should try.  If you’ve answered c) then well done that man (or woman) with balls of steel (or…  erm…  boobs of…  no, sorry, don’t know where I can take that)!  Lets rock and roll!

There are three other things I should point out at this point.

1) You will need SetCPU which is $1.99 from the Market. This is needed for pretty much any Android Device overclock, so worth the small £1.25 investment.

2) I didn’t write any of the scripts or apps involved in this guide, so the support I can offer is limited.  This guide is mainly other people’s guides patched together into one place.

3) I cannot take ANY responsibility if you should end up with a £450 paper weight, even if you follow this guide to the letter.

This is not my work.  A HUGE thanks to the people on XDA Forums for their efforts  - sfjuocekr, Apache14 and of course Paul O’Brien from MoDaCo.

I’m going to assume you’re starting from a fairly blank slate, you’ve done no tinkering before.  If you have, probably best to remove anything like VISIONary and Superuser, with their data so we can start fresh.

Preperation

Okay, lets download everything we’re going to need and get ourselves ready.

1) Backup anything you value from your device.  This guide should leave all your data in tact, but any time you tinker you should backup anything that might lead to a) or b) above if lost.

2) Download the latest version of VISIONary+ from this thread and install it on your device.

3) Download Terminal Emulator from the Market on your DHD.

4) Install SetCPU from the Market.

5) Download the S-OFF script from this thread. (DHD-v0.3.zip at time of writing)  Extract this to a DHD folder on your SD card. (Make sure you have just one DHD folder, not another inside it)

6) Download the latest Android SDK and unzip it to ‘C:\Tools’ on your PC.

7) Download UV-BUZZ-ACE.rar from this thread and put the two files into your C:\Tools folder made in step 6.

Download the latest version of HTC Sync and install it.

Permroot and S-OFF

S-OFF refers to removing security.  This is needed for flashing custom ROM’s and generally for mucking about in what would normally be a protected area.  Sorry HTC!  We wants ta tinker!

9) Run VISIONary+ and select temproot.  Don’t select any of the tick boxes.

10) Once this is done, run VISIONary+ again and select permroot.  Again, no other options selected.  Your DHD will reboot.

11) Open up Terminal Emulator and enter ‘su‘ and you should be asked to grant root access.  Do so and your symbol will turn to a #.

12) Type ‘sh /sdcard/DHD/check‘ and it will check the file for you.  This is where things have the potential to go very bad for your DHD. Follow the on screen instructions, but DO NOT ADVANCE IF THE TWO CHECKSUMS ARE NOT IDENTICAL AT ANY POINT AFTER THE CHECK.  If yours don’t match, you’re best to check this thread for advice.  DO NOT REBOOT YOUR PHONE UNTIL ADVISED SAFE TO DO SO.  I believe if they don’t match, generally just download the DHD-V0.3.zip again.

There will be one error when you finally do ‘sh /sdcard/DHD/hboot‘ which will say insmod: init_module ‘/data/local/wpthis-lovinglymadeforyoubymodaco.ko’ failed (Function not implemented). This is fine, don’t worry.

The Overclock & Undervolt

Hopefully you’ve come through that bit safe and sound and we can move on to the Overclock and undervolt.

13) Shut down your DHD (don’t forget to turn off fast boot in Settings -> Applications to properly shut down)

14) Hold Volume Down while turning on your DHD.

15) Once booted into the Bootloader, select Fastboot by pressing your power button.

16) Connect your DHD to your PC via USB cable.  Wait for drivers to install.

17) Open terminal on your PC and cd to C:\Tools

18) Type fastboot devices and you should see your DHD listed.  If not, the USB drivers are not properly installed.

19) Type the following into the command prompt on your PC -

fastboot flash zimage zImage

This should upload a file to you DHD and flash it over the original.

20) Reboot the phone by typing – fastboot reboot

21) Wait for your DHD to reboot and then type the following into the command prompt on your PC -

adb push bcm4329.ko /sdcard/bcm4329.ko
adb shell
su (authorise root access on your device)
mount -o remount,rw /dev/block/mmcblk0p25 /system (that’s zero p twentyfive)
cat /sdcard/bcm4329.ko > /system/lib/modules/bcm4329.ko

22) Run SetCPU, press menu, select ‘Device Selection’ and then choose ‘Autodetect Speeds Recommended’.  It will ask for root access, which you should authorise.

You should be able to slide it up to 1209 MHz.  You’re done!

If you’re the brave one that tries this first, please report back in the comments below if you have any problems, or if it worked.  If there are issues, I will correct ASAP.  If it works, I’m sure people will be more comfortable in doing it themselves.

**UPDATE** I’ve now moved up to 1497mhz with the files from this thread.  (Use the same method as above) My Desire HD just clocked 52 on Linpack and 2,600 on Quadrant!  Wow!