[HTC One X] MrGarak:
Big thanks to bagofcrap24 for his great original guide here.

This one is for OS X users with an administrator account, I did it in OS X (Lion) because I haven't got the Android SDK installed on Windows at the moment and didn't want the hassle of downloading it just for the USB drivers.

If you get the [Waiting For Device] message in Windows Command Prompt and have access to a Mac instead, you might also want to try this guide.

If you get 'Permission Denied' in Terminal try this.

If I made any errors let me know and I'll correct it.

UPDATE: If you see any errors on HTC-dev such as "We are sorry, but this section of site is temporarily closed." just be patient, wait a little while and try again.

Unlocking Your Bootloader

Before we can even think about doing anything the first port of call is unlocking your bootloader.

As of the time of writing this there is currently no S-OFF method available so this is the only method of flashing a new recovery or boot image.

I'm going to keep this as simple as possible.

1. Go Here "http://www.htcdev.com/" and create yourself an account on HTCDEV.

2. Download this fastboot file for Mac.

3. Make a new folder on your desktop called 'fastboot'.

4. Extract the file 'fastboot-mac' from the .zip downloaded in step 2 to this 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 10 seconds.

9. Power your phone on by holding power and volume down.

10. Highlight Fastboot with volume +/- then press power.

11. Plug your phone into your Mac and open a Terminal window.

12. Type this into your Terminal window:

13. Select & copy the text as per step 9 on the HTCDev website.

Terminal will add some characters to the left of the token, compare yours with the HTC example token, copy your token into the Textedit application and remove the text along the left to make them match, then copy the token again.

14. Paste your identifier token into the box at the bottom and submit.

You will receive an e-mail shortly from HTCDev with a link to the second part of the instructions and your "Unlock_code.bin" attached.

15. Download the "Unlock_code.bin" from the e-mail and save it to the same folder that we extracted fastboot files to in step 2.

16. Type this into your Terminal window:

17. The Display Will change on your phone, press Vol + to accept and power to confirm.

Congratulations, you have successfully unlocked your bootloader.

Now to the good stuff..

Installing A Recovery

This one is very simple to do once you have your bootloader unlocked.

A thing to note; at present there is no USB-Mass Storage in recovery so if you are planning to install a custom rom i would get it put on the internal memory of your phone now rather than messing things up later and been unable to install it.

(if you have follwed my unlocking guide skip to step 4)

1. Download this fastboot file for Mac.

2. Make a new folder on your desktop called 'fastboot'.

3. Extract the file 'fastboot-mac' from the .zip downloaded in step 2 to this folder.

4. At Present The Latest Recovery is an Interim made by Paul O'Brien from Modaco, you can grab it HERE

P.S. its the top one out of the two, the bottom is stock recovery.

Update: Latest official touch and non-touch recovery versions by Koush are available here.

5. Download the custom recovery and save it in the same folder as you did the fastboot files.

6. Power the phone off by holding the power button for 10 secs.

7. Select Fastboot with volume + or - then press power.

8. Plug your phone into your Mac and open a Terminal window.

10. If you still have the Terminal window open from installing your bootloader then skip to the next step, if not then type this into your Terminal window:

11. Type this into your Terminal window:

Congratulations, you now have a custom recovery.

Flashing A ROM

1. Select reboot bootloader with volume +/- then power to select

2. Select HBOOT with volume +/- then power to select

3. Select recovery with volume +/- then power to select

You are now on your custom recovery.

4. First things first - do a Nandroid Backup of your current ROM in case anything bad happens.

5. Make sure you already have your shiny new ROM .zip on your internal memory as you cannot enable mass storage in the current recovery builds.

6. Wipe then flash your new custom ROM.

(You can flash the Super Wipe .zip from here to easily wipe your system partition and prepare it for the fresh ROM, thanks mike1986.)

OR you can download the latest SuperSU binaries from HERE and install them Via Recovery to just root the stock ROM.

Hope this helps some of you.