Here's a tutorial for the new users facing unanswered (at a first glance) questions while browsing through the tremendous amount of information that can be found.
There are many tutorials about this, but I will try to make one unique tutorial that will be easy to understand for everyone.

Press a THANKS button if you think that this TUT has helped you

IMPORTANT!
Before you proceed, you need to understand one thing: although these upgrades work in 99% of the cases, you are doing this at your own risk!
If you have any problems or question with rooting and flashing ROM's DO NOT open new thread, cause I will delete it, post everything here

Before we start, here is little Q&A section, so please READ this before opening new thread!
How to format and partition SD Card?
Read this
Is my desire already rooted?
- Check if you have superuser app in the app list all rooted phones have it
If I root a device which is already rooted, can it mess anything up?
- You can't mess anything up by re-rooting.
Will my phone get the OTA froyo update from HTC here in the US or do I have to do it manually?
- No OTA updates when rooted, to get them you will have to go back to stock to get the update(yepp unroot, or wait for devs to release rooted stock version)
What is S-OFF?
-HTC implemented security on their newer generation phones. This flag, called @secuflag, controls whether your phone has
it's NAND or flash unlocked. Most noticeably, S-ON (security on) will read-lock your /system and /recovery partition, to name a few. Also, secuflag controls whether zip files being flashed through recovery or fastboot, are signed by HTC. The now notorious S-OFF (security off) will disable this NAND security. Since we are unable to access the Radio NVRAM itself (where secuflag is stored), we turned our attention to HBOOT.
Here is How to S-OFF your HTC Desire
If you think I should add more questions and answers, send me a PM



The easiest root method of all is(works for any Desire!):
[GUIDE] One Click How to Root the GSM & CDMA Desire with Unrevoked 3.21


If you want to root using old method, and you have Android 2.2 you will need to downgrade your radio first
[HOWTO] Downgrade Froyo (2.2) to Stock 2.1 (ANY HBOOT | WIN/LINUX/MAC | ROOT)
or
[HOW-TO] downgrade HBOOT 0.92 to 0.80 again
Here is how this thread works:

• Newbie Friendly How To's w/ Instructional Videos(tnx to dcogen) - post #1
• Root guide for users who have unbranded(unlocked) Desire - post #2
• Root guide for users who have branded(locked) Desire and
• How to make GOLDCARD - post #3
• Guide how to use fake-flash, unroot, flash ROM and updates - post #4
• How to remove apps & boot sound, install apps, and many other things - Post #5
  *Unrooting, flashing ROM and updates is same for every device.

• How To Setup ADB
  
• How To Load a Theme
• How To Flash a New Recovery Image
• How To Switch to a Different SD Card (for use with Swap, Hero ROMs, etc.)
• How To Backup/Restore Your Android Phone
  
  HTC Desire How To's
• How To: Root the HTC Desire
  
• How To: Load a Custom ROM on the HTC Desire
• How To: Unroot the HTC Desire

Guide to root with Tiny Core Linux
IMPORTANT - this tutorial will not work if you have installed 2.2 OTA update from HTC!

1. Download Tiny Core Linux Live CD
   ---- For a bootloader of 0.75.* or lower AND a current ROM of 1.15.* or lower Download
   ---- For a bootloader of 0.80.* or lower AND a current ROM of 1.21.* or lower Download
2. Burn the downloaded iso on CD/DVD
3. Boot your computer from that CD/DVD, once you booted it will ask you to press Enter or F2/F3 keys, you need to press Enter
4. Start the HTC Desire in bootloader by holding back and turning it on by the power button
5. Connect the USB cable to the phone and PC
6. Open a terminal by clicking the icon that looks like a monitor at the bottom on Tiny Core Linux and type the following commands:
   
   Code:

   sudo mkdir /mnt/cdrom
   sudo mount /dev/cdrom /mnt/cdrom
   cd /mnt/cdrom/desire
   sudo ./step1.sh

7. Wait until the phone restarts back into the white bootloader screen
8. In terminal type the following command:
   
   Code:

   sudo ./step2.sh

9. Once the phone has finished, you will see a screen with a green text. Use the optical tracker to navigate the menu to select Wipe and then press Wipe data/factory reset
10. Once complete you should be back in the main menu. Now select the option Flash zip from sdcard and than choose rootedupdate.zip
11. Once back in the main menu, choose restart the phone - the rooting process is now finished

1. !Some people reported that this method needs to have GoldCard(in most cases you won't need it) even if you have unbranded device, more here
2. You need to have Android SDK and HTC Sync installed(for Windows users)
3. Download following items:
   ---- If you have a bootloader version 0.75.xxxx or below AND a current ROM of 1.15.xxx.x or below - DOWNLOAD / MIRROR
   ---- If you have a bootloader version 0.80.xxxx or below AND a current ROM of 1.21.xxx.x or below - DOWNLOAD / MIRROR
4. Unzip the file you downloaded to a directory, then open a command prompt / terminal window at that directory.
5. Turn off your HTC Desire, then turn it back on with the 'back' button held down. You'll see 'FASTBOOT' written on the screen in a red box. Connect the phone to the computer.
6. In the command prompt/terminal window, enter either 'step1-windows.bat'(for windows), './step1-mac.sh'(for mac) or './step1-linux.sh'(for linux)
7. Navigate to the 'BOOTLOADER' and then 'RECOVERY' option on the menu, using the volume buttons to move and the power button to select.
8. In the command prompt/terminal window, enter either 'step2-windows.bat', './step2-mac.sh' or './step2-linux.sh' as appropriate.
9. When this has completed, your device should be at the 'recovery'("green") screen. Select Wipe and then press Wipe data/factory reset
10. Once complete you should be back in the main menu. Now select the option Flash zip from sdcard and than choose rootedupdate.zip
11. Once back in the main menu, choose restart the phone - the rooting process is now finished

Before you start to root your branded(locked) Desire you need to know:
How to make GoldCard

GoldCard Tool v0.0.5
Requirements:

• Latest HTC Sync software installed (www.htc.com)
• Spare microSD card
• Windows PC (Tested on Windows7 x64,Vista x86)
• .Net Framework 2.0

• Format the microSD card to FAT32 format.
• Put the microSD card in your device and boot it.
• Launch GoldCard Tool (Right Click and run as Admin if needed)
• Connect Android device to USB (USB Debugging must be enabled on the device)
• Click 'Get CID' (If MMC1 fails try MMC0)
• Click the link to open revskills.de, enter the CID number from Goldcard Tool and create your goldcard image, which will be e-mailed to you.
• Enable USB Mass Storage on the device.
• Click 'Refresh' and select your microSD card in the drop down menu.
• Click 'Load GoldCard.img' and open the .img file you got by email.
• Click 'Patch MMC'

1. Download Tiny Core Linux Live CD
   ---- For a bootloader of 0.75.* or lower AND a current ROM of 1.15.* or lower Download
   ---- For a bootloader of 0.80.* or lower AND a current ROM of 1.21.* or lower Download
2. Burn the downloaded iso on CD/DVD
3. Boot your computer from that CD/DVD, once you booted it will ask you to press Enter or F2/F3 keys, you need to press Enter
4. Insert the goldcard into the phone.
5. Start the HTC Desire in bootloader by holding back and turning it on by the power button
6. Connect the USB cable to the phone and PC
7. Open a terminal by clicking the icon that looks like a monitor at the bottom on Tiny Core Linux and type the following commands:
   
   Code:

   sudo mkdir /mnt/cdrom
   sudo mount /dev/cdrom /mnt/cdrom
   cd /mnt/cdrom/desire
   sudo ./step1.sh

8. Wait until the phone restarts back into the white bootloader screen
9. Turn the phone off via the bootloader menu (or pull the battery and USB cable) and remove the goldcard. Put a non-goldcard SD into the phone or reformat the goldcard and put it into the phone. Put the phone back into bootloader mode (Press Power button and Back button).
10. In terminal type the following command:
    
    Code:

    sudo ./step2.sh

11. Once the phone has finished, you will see a screen with a green text. Use the optical tracker to navigate the menu to select Wipe and then press Wipe data/factory reset
12. Once complete you should be back in the main menu. Now select the option Flash zip from sdcard and than choose rootedupdate.zip
13. Once back in the main menu, choose restart the phone - the rooting process is now finished

1. Download following items:
   ---- If you have a bootloader version 0.75.xxxx or below AND a current ROM of 1.15.xxx.x or below - DOWNLOAD / MIRROR
   ---- If you have a bootloader version 0.80.xxxx or below AND a current ROM of 1.21.xxx.x or below - DOWNLOAD / MIRROR
2. Unzip the file you downloaded to a directory, then open a command prompt / terminal window at that directory.
3. Turn off your HTC Desire, put GoldCard and then turn it back on with the 'back' button held down. You'll see 'FASTBOOT' written on the screen in a red box. Connect the phone to the computer.
4. In the command prompt/terminal window, enter either 'step1-windows.bat'(for windows), './step1-mac.sh'(for mac) or './step1-linux.sh'(for linux)
5. Turn the phone off via the bootloader menu (or pull the battery and USB cable) and remove the goldcard. Put a non-goldcard SD into the phone or reformat the goldcard and put it into the phone. Put the phone back into bootloader mode (Press Power button and Back button)
6. Navigate to the 'BOOTLOADER' and then 'RECOVERY' option on the menu, using the volume buttons to move and the power button to select.
7. In the command prompt/terminal window, enter either 'step2-windows.bat', './step2-mac.sh' or './step2-linux.sh' as appropriate.
8. When this has completed, your device should be at the 'recovery'("green") screen. Select Wipe and then press Wipe data/factory reset
9. Once complete you should be back in the main menu. Now select the option Flash zip from sdcard and than choose rootedupdate.zip
10. Once back in the main menu, choose restart the phone - the rooting process is now finished

fake-flash
Fake-flash is only possible with root access, you need to be rooted to use it. Basically, its a way to have recovery running on the phone without using a PC (making it safer as you are less likely to brick using no USB cable to push files, instead, you push directly from your phone). You can use "ROM Manager" from the marketplace to do this. Simply place the downloaded test recovery image on the phone and the downloaded rom zip (renamed to update.zip) and flash using ROM Manager.
Preperation

• Download the fake-flash update zip from one of the links below
• Copy the update.zip to the root of your SD card (the name MUST remain as update.zip)

• Turn on your device with 'volume down' pressed and select 'Recovery'
• When the exclamation mark appears, press and hold 'volume up' then press 'power'
• Select the second option, 'Apply sdcard:update.zip
• That's it, ClockworkMod recovery should launch!

1. Download this
2. Turn off Desire and then turn it on while holding back button to enter bootloader(white screen)
3. Once in "white screen" press power button again to enter bootloader
4. Connect Desire with PC
5. Press Volume Down and than Power to enter Recovery
6. Now the red triangle should show up, go to folder you downloaded file and press recovery-windows.bat, recovery-mac.sh or recovery-linux.sh depending on which OS you have
7. Now you are in recovery mode (green screen), press Wipe and than Wipe data/clear storage, than press optical tracker to confirm it
8. After that press Volume Down to go back to main menu in recovery
9. Navigate to Flash zip from sdcard using optical tracker, select .zip confirm it and wait until process finish, after that press Reboot system and unplug you Desire
10. Enjoy your new ROM

1. Download this
2. Copy bootanimation.zip to SD Card
3. Turn off Desire and then turn it on while holding back button to enter bootloader(white screen)
4. Once in "white screen" press power button again to enter bootloader
5. Connect Desire with PC
6. Press Volume Down and than Power to enter Recovery
7. Now the red triangle should show up, go to folder you downloaded file and press recovery-windows.bat, recovery-mac.sh or recovery-linux.sh depending on which OS you have
8. Navigate to Flash zip from sdcard using optical tracker, select .zip confirm it and wait until process finish, after that press Reboot system and unplug you Desire
9. Unplug your HTC and enjoy your new boot animation

1. You need to have HTC Sync and Android SDK installed (http://developer.android.com/sdk/index.html).
2. To get adb running on the Windows OS platform, for example, download & extract the Android SDK to the following path: %SystemDrive%\android-sdk-windows (e.g. C:\android-sdk-windows)
3. Turn on your phone and connect it to your PC via a USB port.
4. Place the downloaded bootanimation.zip into the same folder as the adb app (in the tools folder of the SDK).
5. Open command prompt and type cd C:\android-sdk-windows\tools, hit enter.
6. Type adb push bootanimation.zip /data/local, hit enter.
7. Reboot phone.

1. HTC Sync (For Drivers)
2. The Download Above
3. A Windows PC
4. A Goldcard (Not required for generic HTC Desires)

1. Make sure your goldcard is in your phone (If Required-if your phone is branded)
2. Turn your Desire on
3. Connect it to a Windows PC
4. Run the HTC RUU
5. Let it run
6. & YOUR DONE!

How to remove apps from ROM
You need to have root for this and Android SDK installed!
Link to detailed tutorial

Im using Paul's R4 rooting files at the location C:/users/veedubz/r4-desire-root in Windows 7 so point your Command prompt there first and im also assuming that you have a rooted Desire and can get into recovery mode
1. First get into recovery mode with the Green menu then close that command prompt and open a new one and cd to /r4-desire-root folder

2. You now need to mount the /system folder using the code below

adb-windows shell mount /system

3. Now you will need to get the list of installed apk files

adb-windows shell ls /system/app/

and the output should look like this:

AccountAndSyncSettings.apk		 HtcWeatherWallpaper.apk
ApplicationsProvider.apk		   Jbed.apk
Bluetooth.apk					  LiveWallpapers.apk
.....                                                     ......
HtcStreamPlayer.apk				htcsettingwidgets.apk
HtcSyncwidget.apk				  restartapp.apk
HtcTwitter.apk					 teeter.apk

4. there are 2 methods of removal, they are

1. 4a. Just delete the files
2. 4b. Move to the sdcard

adb-windows shell rm /system/app/Stock.apk
adb-windows shell rm /system/app/com.htc.StockWidget.apk

4b. Also case sensitive, to move the files to your sdcard(which aso removes from the device):

adb-windows shell mount /sdcard
adb-windows shell mkdir /sdcard/device_files
adb-windows mv /system/app/Stock.apk /sdcard/device-files
adb-windows mv /system/app/com.htc.StockWidget.apk /sdcard/device-files

The files will be moved to the new folder on your sdcard called /device-files, once there you can also backup to your pc for a bit of extra backup
5. Repeat Step 4. untill all the apk files that you want to remove are gone and to check that they are gone use

adb-windows shell ls /system/app/

Restoring your backed up files

Use the following code,

adb-windows shell mount /sdcard
adb-windows shell mv /sdcard/device-filesStock.apk /system/app/
adb-windows shell mv /sdcard/device-files/com.htc.StockWidget.apk /system/app/

How to remove apps from ROM
Read here

any one having trouble downloading the method5 for windowsfiles for hboot 0.8
the first link seems dead and the mirror downloads a corrupt file ??

...EDIT --- forgEt this post liknk 2 seems fine now THANKS !!! .. .... .....

OH and nice work

Thanks man for this guide.
It's more clear for me now =)

cheers - if i flash R5 rom,will this leave me with 121 rom or 115 rom? -I already running the 121 rom?

thanks

Originally Posted by dread123  

cheers - if i flash R5 rom,will this leave me with 121 rom or 115 rom? -I already running the 121 rom?

thanks

You will have generic 1.15 ROM

Good job!!!