First off, I take no credit for this guide, this is straight from the xda-developers forums, which is an excellent place to learn about HTC phone hacking. So let’s get started. Make sure you backup anything important on your phone as this will erase everything. There are several apps in the Market that will backup apps, SMS, and other data for you. So don’t complain if you’ve lost your data. Your contacts and email should still synch with Google once you reinstall the new OS.

If you have US-RC30/UK-RC8 or higher, you will first need to downgrade your phone to a previous version. (Skip these steps otherwise)

1. Format your phone’s SD card to FAT32 mode:
   • Hook your phone up to your computer using a USB cable and then wait for the notification to show up in your title bar of your phone.
   • Click the notification, and then click “Mount”.
   • A new removable disk should show up on your computer. Right click it and select Format, and select FAT32 as the file system type.
2. Download and unzip the RC29 or RC7 image file. Copy the DREAMIMG.nbh file to the SD card. (RC29 for US, RC7 is for UK)
3. Turn the device power off.
4. Hold Camera button, and press Power button to entry bootloader mode. You should see a gray/white screen with instructions to flash your phone with the update on your SD card. If you don’t see that, make sure you followed the instructions properly.
5. As per the on-screen instructions, press the Power button to start upgrade procedure.DO NOT DO ANYTHING TO INTERRUPT THIS PROCESS.
6. After it is finished, perform the restart your phone.

Once you are running RC29 firmware:

1. Download recovery.img and copy it to your SD card (see the previous instructions on how to copy from your computer to your Phone’s SD card).
2. Download the Hard SPL and copy the zip file to the SD card.
3. All files must be on the root of your SD card.
4. Restart your phone. Wait for your phone to start up fully and show the home screen.
5. After your phone starts up, hit the enter key twice, type “telnetd” and press enter. (Yes, it will start up a contact search, don’t worry. Just type it.)
6. Download an Android “Telnet” application from the Market and connect to localhost.
7. If you connect successfully, you will have a root prompt “#”.
8. Type the following into Telnet (these commands will give you root access easier in the future):
   • mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system
   • cd sdcard
   • flash_image recovery recovery.img
   • cat recovery.img > /system/recovery.img

Now you have root!
Now that you have root, you will want to apply “Hard SPL” to your phone. HardSPL is what will allow you to apply flash images from other regions (like UK on US phones, and vice versa), create full backups of your phone, install the latest build from the Android source, and usually resurrect your phone if it is “bricked”. You have already downloaded the file to your SD card, so now you can apply it.

1. Power off your phone.
2. Start up in recovery mode by holding home and pressing power.
3. You will now enter recovery mode. You should see an exclamation.
4. If you do not see a menu on screen, press Alt-L to show the menu.
5. Press Alt-S to apply the update from the SD card.
6. After the update is complete, hold Home and press Back to restart.

And now, the last step! You are still running an old version of Android, but you want to upgrade to the latest and greatest update! You can do this, and not lose root by downloading modified versions of the updates.

Download one of the latest ROMs to install, I recommend JF1.5:

JesusFreke 1,51

Haykuro Builds

The Dude’s Cupcake 1.2 Full
The Dude’s Cupcake 1.1a Lite (No 3rdparty/dev apps/Manup Blue Theme)

You will also want to apply the latest radio update from HTC. Install the same way as the system image:

HTC Downloads Page

To install the latest build (instructions from Haykuro):

1. Gain root (follow the various threads available on the forums to accomplish this).
2. Download the latest build above.
3. Copy to your sdcard as update.zip
4. Power off your phone.
5. Hold the Home button, and power on the device. (This should send you into recovery mode).
6. Press ALT+B to create a nandroid backup (if you wish to fall back without losing any data later, if you do go back to RC33 [or any other firmware 1.0 update] you will need to reflash your radio, users have reported problems using the new radio on the old firmwares.)
7. Press ALT+W, then ALT+S.
8. wait for it to finish, then home+back.

There you have it. I hope I gave proper credit and backlinks to the awesome people that make this possible. Now you can brag about your new Cupcake and also do all the cool stuff with root, like install full Linux distros, tether your phone, and install apps on the SD card.