Do this AT YOUR OWN RISK and I don't guarantee it will work on all Htc One V (but successfully done on my Htc One V (PrimoU)).
First: Credits go to:
1) paulobrien for his tools & guide
2) bagofcrap24 for the stolen unlocking bootloader tutorial..
Second: It is good to have official RUU for your Htc One V version. You can find the official RUU HERE(credit : JMZ) & HTCSync in case you something goes wrong and you need to revive your One V.
Or make a nandroid backup after you successfully unlock the bootloader. How ? Read further below. So read fully before you attempt to unlock bootloader and rooting.
Third: the tutorial
Unlocking Your Bootloader
Note: After doing unlocking bootloader, all your data/apps are gone so make a backup to your PC first.
You will need to run the initial setup again.
1. Go Here "http://www.htcdev.com/" and create yourself an account on HTCDEV.
2. Download These Fastboot Files
3. Make a new folder on your C: drive called fastboot.
4. Extract The Zip downloaded in step 2 to the new folder
5. Go Here http://www.htcdev.com/bootloader/ and select "All Other Supported Models" and "then begin unlock bootloader"
6. Yes, Tick both Boxes, Proceed
7. Skip up to step 8 as we have all we need for the first 7 steps
8. Power off your phone by holding the power button down for 5-7 seconds (the three keys will flash a few times then it will power off)
9. Hold volume down button, the device will boot to HBOOT
10. Select Fastboot With Volume+or- then press Power once (you'll be in fastboot mode)
11. plug your phone into your PC and open a Command Prompt.
(windows XP - Click Start > Run > type CMD in box then press OK
(Windows 7 - Click Start > type CMD in search box then press Enter)
12. cd to your folder where we put fastboot files cd c:\fastboot
13. type this into your command prompt window fastboot oem get_identifier_token
14. select & copy the text as per step 9 on the HTCDev website
15. paste your identifier token into the box at the bottom and submit
You Will Very Shortly Receive an email from HTCDev with a link to the second part of the instructions and your "Unlock_code.bin" attached
16. download the "Unlock_code.bin" from the email and save it to the same folder that we extracted fastboot files to in step 2
17. type this into your command prompt window fastboot flash unlocktoken Unlock_code.bin
18. The Display Will change on your phone, press Vol + to accept and power to confirm.
Congratulations You Have Successfully Unlocked Your Bootloader
UPDATE: Read the IMPORTANT note added below
Rooting with Superboot for GSM Device (Primo U)
1. Download r1-primo-superboot.zip to your computer and extract in any directory.
2. Download the modded boot.superboot.img
3. Replace the boot.superboot.img in the folder that you extracted just now (r1-primo-superboot).
Or download one of the Superboot that relevant to your device HERE
4. Power off your phone by holding the power button down for 5-7 seconds (the three keys will flash a few times then it will power off)
5. Hold volume down button, the device will boot to HBOOT
6. Select Fastboot With Volume+or- then press Power once (you'll be in fastboot mode)
7. Connect your phone to PC
8. Double click ‘install-superboot-windows.bat’
Rooting with Superboot for CDMA Device (Primo C)
1. Download r1-primo-cdma-superboot.zip to your computer and extract in any directory.
2. Power off your phone by holding the power button down for 5-7 seconds (the three keys will flash a few times then it will power off)
3. Hold volume down button, the device will boot to HBOOT
4. Select Fastboot With Volume+or- then press Power once (you'll be in fastboot mode)
5. Connect your phone to PC
6. Double click ‘install-superboot-windows.bat’
Once it complete, the phone will reboot on its own. In app drawer you will see a SuperSU icon, click on it and update SU binary then you are done with rooting your Htc One V.
You can try any app with root access to confirm it is working.
As some people forget to make a nandroid backup for their stock ROM, after they successfully unlocked their device,
when a soft brick happens, it will be a big problem to be back on stock when they are unable to find the official RUU for their device.
So make sure, after successfully unlocked your device, don't do anything else yet, flash the CWM recovery and make a nandroid, make nandroid and nandroid of your stock ROM.
Download the Recovery for GSM Device:
CWM 5 - http://forum.xda-developers.com/show...php?p=28153112
Direct download link : http://download.clockworkmod.com/rec...4.5-primou.img
CWM 6 - http://forum.xda-developers.com/show....php?t=1871243 (the latest version as at 05 Sep 2012)
Download the Recovery for CDMA Device:
CWM - http://forum.xda-developers.com/show....php?t=1749798
How to make a nandroid backup ?
Once the CWM recovery installed:
Press power once (to go to hboot)
press volume down/up to navigate the menu to RECOVERY, press POWER once
Once in the RECOVERY menu:
click backup and restore
the backup process is running. It will be a few minutes to complete.
once complete, check whether the backup is successful
click backup and restore
you will see your backup files, e.g: 2012-06-12.0.13.04
click Go Back or use the back button
click reboot system now to boot your device
once fully booted, mount your sdcard to PC, browse to \clockworkmod\backup and copy the 2012-06-12.0.13.04 folder to your PC as a second backup in case something is wrong with your sdcard.
2012-06-12.0.13.04 is an example only, you will get a different no.
Alternatively, you also can use TWRP recovery:
GSM version - http://forum.xda-developers.com/show....php?t=1721749
CDMA version - http://forum.xda-developers.com/show....php?t=1764183
Now you are ready to do the rooting process.
Once your device is rooted, you are free to do whatever you want to do with your device, to flash a custom ROM, a custom kernel... whatever.
If soft brick happens and there is no official RUU, a stock nandroid backup may helps you