[HTC Desire V] :
Ok, so you have a device with stock ROM and you just rooted it?

I don't know if you have unlocked bootloader, but let's take it from the begining:

0. First you need an official RUU of your stock ROM for backup, and for signed boot and recovery. Try to find the most recent one. There are a few over the internet, but they are different by CID phone. Mine for example has a China Unicom CID and I have to find a RUU that starts with that: RUU-PRIMO-DS-ICS-40A-HTCCN-CHS-CU... and ends with ...-signed.exe.

In your build.prop file in phone /system/ folder you'll find exact model, look for this line "ro.build.fingerprint=

htccn_chs_cu

/htc_primods/primods:4.0.3/IML74K/118315.3:user/release-keys".

Other options are RUU-PRIMO-DS-ICS-40A-hTC-Asia-WWE... which I think is India, RUU-Primo-DS-ICS-40A-HTC-Europe... Europe and RUU-PRIMO-DS-ICS-40A-hTC-Asia-TW... Taiwan. Search for yours and save it.

1. You have to unlock bootloader (this will void your warranty) if you haven't done yet:

Go to http://www.htcdev.com/bootloader/

In the box searching for model (right of page) select "Any other model"

Follow the steps as they guide you

- After you receive Unlock_tocken.bin keep it in a safe place in case you need it again in the future.

2. You need Adb Tools for flashing

Go to this page http://www.jailbreakeye.com/android/install-adb-fastboot or this http://xdaforums.com/showthread.php?t=690362, read carefully and follow the steps.

For drivers you can check this page http://xdaforums.com/showthread.php?t=2217396.

3. Reboot to bootloader as I wrote in first post and flash a custom recovery (you can get one here in my first post or from this post http://xdaforums.com/showthread.php?p=37281787#post37281787 of Aka_Noodle)

4. Reboot in recovery and do a nandroid backup of your stock ROM, if you want to revert to that in case you don't like a custom ROM.

5. Reboot in bootloader again and flash the boot image for the ROM you want to try.

6. Copy the zip of the new ROM on your sdcard

7. Reboot in recovery, flash the zip

8. Reboot the phone and you're done!

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Ok, I just find some universal tool with guides and everything: http://xdaforums.com/showthread.php?t=2200660

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If you want to revert to stock:

1. Reboot in Recovery, wipe Dalvik cache - wipe all data/factory reset - restore the backup of your stock ROM

2. Reboot to bootloader and flash a signed boot image

3. Reboot phone, see if everything it's working

- 4. Now if you really want to go back to stock for OTA updates: Unroot the phone, Reboot bootloader, flash a signed recovery, relock phone in fastboot, and reboot.

For any of these steps there are plenty of guides on this forum, so I didn't want to copy them here. But if you search the forum you will find anything you want. These opperations are not specifics to HTC Desire V, but for all Android phones, except unlock bootloader. I just show you the steps in order as I do these things.

I hope you get the ideea, but if you don't,before do anything tell me exactly what you didn't understood and I'll try to point you in the right direction.

Anyway, these things are dangerous for your phone and you risk to brick it. So, if you're not feeling confortable to do these things find a friend who did something like that before and ask him.

I'm not responsable if you brick your phone.