HTC One S can be updated to the new official version of One MaximuS 1.78.401.2 custom ROM by reading all the instructions listed in the tutorial guide. One MaximuS has been created by Football, an XDA developer.

This new ROM maximizes and improves the overall performance and prolongs the battery life of your One S smartphone. It comes without any bloatware applications which means that you won't have to deal with any stock applications. It brings improved RAM, Fast and Smooth UI, the HTC Hub application now works, you can select any language you wish, the feedback apps have been deleted while all the other Android apps have been updated.

Before updating your One S using the One MaximuS ROM custom firmware you will need to read the info listed below as you will learn how to properly configure your smartphone and computer so that everything will complete successfully. Here's what you need to know:

  • this guide only works with the HTC One S device. Do not attempt to install the One MaximuS ROM on any other smartphone or tablet.
  • create backups of all your video, audio, pictures and all other important files. Move them on your devices internal or external SDcard as these will remain untouched by the updating files.
  • Text messages can be easily saved using the SMS Backup & Restore for Android.
  • Call Logs can be saved and then restored using the Call Logs Backup & Restore Android app.
  • your phone Contacts can be synced with your Gmail account so that you will be able to restore them on your phone after the custom ROM has been installed. Here's a guide to help you sync Android Contacts with Gmail.
  • enable the USB Debugging option.
  • charge your phone battery until reaches at least 75% and this will prevent it from powering OFF.
  • disable all antivirus applications so that no other app will interfere with the installation process.
  • it is recommended to save the APN and MMS Settings. These will allow you to restore the internet settings in case you won't be able to browse the web after the custom ROM update.

How to update the HTC One S with One MaximuS ROM firmware:

  1. First thing you need to do is to unlock the One S bootloader and then install the CWM recovery. All the tools you need are listed in this guide here.
  2. Download the One MaximuS ROM zip firmware fils from here.
  3. Now copy the custom ROM zip on your phone's internal SDcard. Disconnect the device from your PC.
  4. Download the Android fastboot kit from here. Save this file on your PC.
  5. Extract the contents of 'Android fastboot kit' into a single folder on your computer desktop screen. The folder should be renamed to Android.
  6. Power off your HTC One S.
  7. Boot the device into bootloader mode. This can be done by pressing and holding simultaneously the 'volume down' and 'power' buttons. Select fastboot and press Power to enter the 'fastboot' mode.
  8. When in fastboot mode you will need to connect your HTC One S to your computer.
  9. Open the 'Android' folder you've created at step 5 and double click the file that says 'install boot.img.bat' file. This action will flash the phone's kernel.
  10. Wait for the kernel to be installed. You'll know that it installed correctly when a screen opens and after that automatically closes by itself.
  11. Now, go back to your phone screen and select 'HBOOT' and press 'power button' to open a new menu. Here select 'Recovery' and launch it. Your phone will boot the recovery mode.
  12. Select the option that says 'wipe data/ factory reset' and confirm its actions by selecting 'YES'. Wait for the data wiping process to be completed.
  13. We need to install the One MaximuS ROM by selecting the 'install zip from sdcard' and then 'choose zip from sdcard'.
  14. Now find the ROM file on your internal SDcard. It should be the one you've moved on your phone at step 3. Confirm its installation  and then wait for the One MaximuS ROM to be successfully flashed.
  15. When the ROM update is complete you will be taken back to recovery. Select '++Go Back++' and then select 'reboot system now'. Your phone will now run its first boot into One MaximuS ROM.

In case the ROM wasn't successfully updated, then you should re-read all the instructions in this post and repeat all the steps found in both, preparation and tutorial, guides. Also, make sure to ask in comments if you can't get past any of the steps in the tutorial guide.

If everything went as it should have gone then you can proudly say that you've managed to update your HTC One S Android phone to 1.78.401.2 One MaximuS custom ROM firmware.

Majid Bardane · 3 years ago

Hi there,

My HTC One S and it This build is for development purposes only
do not distribute outside of HTC
without HTC's permission

Frank P.Kulik · 4 years ago

Hi there,
My HTC One S and it was already running CM 11... but the battery was draining fast so I thought I could better run an older version...
But then I stumbled across your MaximuS rom and thought that would be cool as well... upgrading went ok, but I got only 2GB storage available... 13GB are in use by "other" data... has anybody seen this before?

Daz · 4 years ago

Hi Frank, i have exactly the same situation. Did you fix it?

Frank P.Kulik · 4 years ago

No, so I switched back to CM11...
Let me know if you need instructions for getting rid of MaximumS...

Frank P.Kulik · 4 years ago

The link to the Android fastboot kit is dead... from where to get the mentioned one?

jdom1966 · 5 years ago

Is there not anything you can do to the ONE S without root?????????????

Alex - a curious app developer :) · 7 years ago

Valuable information. Fortunate me I discovered your site by accident, and I'm surprised why this accident did not happened in advance! I bookmarked it.

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