If you don’t want to wait for Android 4.3 Jelly Bean to hit your HTC One, you don’t have to. Android developer LlabTooFeR released his MaximusHD ROM, which includes a leaked copy of HTC’s own 4.3 update, complete with Sense 5.

Warning

This will only work on GSM models of the HTC One. That means AT&T, T-Mobile, and International versions can get 4.3 ahead of time. This will NOT work on Sprint or Verizon models.

I have only tested it with the AT&T version of the HTC One, and not the International or T-Mobile version. It should work fine, though, but your results may vary.

Prerequisites

1. S-OFF
2. Custom recovery installed (I’m using TWRP)

Both of these can be accomplished using our past softModder guide on unlocking and rooting the HTC One.

Step 1: Download the MaximusHD ROM

On your HTC One, head over to this link and download the latest version of the MaximusHD ROM (currently 12.1.0) onto your internal storage. For updated links, check out LlabTooFeR’s blog post.

If you download it directly onto your HTC One, it will be dropped into your Downloads folder, or whatever you have set as your downloads location.

To make it easier to find, you could alternatively download it onto your computer, then transfer the file over to the root of your HTC One’s internal storage.

Step 2: Boot into Recovery Mode

Before we wipe our device, we have to get into recovery mode.

1. Turn off your device.
2. Press and hold Volume Down and Power to boot into HBOOT.
3. Press Volume Down to select Recovery.
4. Press the Power button to confirm.

Step 3: Back Up Your Device

Yes, this ROM unfortunately requires a full wipe of your system, so if you haven’t backed up yet, make sure to do so now. To back up in TWRP, do the following.

1. Tap Backup.
2. Check the boxes for Boot, Cache, Data, Recovery, and System.
3. Swipe to Back Up.

Step 4: Wipe Your Device

Now, let’s use TWRP to wipe our device clean.

1. Tap Wipe.
2. Tap Advanced Wipe.
3. Check the boxes for Dalvik Cache, Cache, Data, and System, as seen below.

4. Swipe to Wipe.
5. Press the Home button.

Step 5: Flash the ROM

You should now have a clean system and the Maximus ROM downloaded onto your internal storage (which we did not wipe in the previous step). Let’s start installing now!

1. Tap Install.
2. Select the MaximusHD .zip file down at the bottom.

4. Swipe to Confirm Flash.
5. Run through the Aroma Installer.

There are a lot of options to setup, keep running through the setup checking off what you would like to install. I suggest letting Maximus perform a full wipe again, just to make sure there are no hitches.

I have not tested any of the additional mods, so if you want to remove HTC Sense, or enable OpenVPN and SQLite Support, that’s up to you. Also, if you think your HTC One wasn’t loud enough, you can increase the sound if you’d like. You can even remove apps that you don’t like in the ROM.

After you are done selecting all the options, it will begin the installation. When it’s done, tap Yes to reboot.

Enjoy Your New ROM!

Since you did a full wipe, you’ll need to set everything back up again. Also, since this is an International ROM, all of the formatting is in international formats (i.e. Celsius, 24-hour clock, etc.).

This can all be changed back to your liking in the device settings (i.e. Fahrenheit, 12-hour clock, etc.).

Want the Official 4.3 Update When It Comes Out?

There are built-in OTAs in MaximusHD, but only for MaximusHD updates. You will not be able to take the official 4.3 OTA from your carrier when it’s released, so you should make a backup of your stock ROM before you flash in TWRP, in case you want to revert back to get the official OTA from your carrier (currently expected to arrive by the end of September).

But as with all ETAs, take that with a grain of salt.