How to update OnePlus One with Android 5.1.1 SlimSaber aka SlimLP ROM

OnePlus One users can now enjoy a fast and smooth Lollipop experience in an extremely lightweight package, thanks to the release of SlimSaber (aka SlimLP) ROM, which is built entirely out of custom toolchain SaberMod for enhanced performance and stability.

The SlimLP ROM is completely bloatware free and offers the best custom Lollipop experience on phones with limited storage resources. Besides, its source code is fully optimised for achieving maximum performance and battery life.

Here is the list of salient features that make this unofficial build stand out from the official SlimROMs:

Compiled with a custom toolchain Sabermod for more performance and better battery life
Compiled with the GCC optimisation level -O3
Compiled with strict-aliasing compiler optimisation
Added patches to fix GCC strict-aliasing violation rules
Added ARMv7 optimised string handling routines for more smoothness and more memory optimisation
Disabled SQLite fsync to increase I/O performance
Cherry-picked some AOSP bug and memory leak fixes
Cherry-picked some KitKat bug and memory leak fixes

Some of the latest bug-fixes and changes incorporated into the SlimSaber bacon Android 5.1.1 ROM are listed below:

WiFi: Patch for DHCP (This should fix WiFi disconnections.)
Frameworks: Another small optimisation
Settings: Slim Recents
You can choose between Stock or Slim Recents
LCD Density: Input DPI value instead choosing it from the list
Settings: Fix notification light colour not showing in settings for Missedcall and Voicemail
Blobs: Update rmt_storage
Bluetooth: Sync bluetooth commits with CM
Apps: Fix CameraNextMod start FC
Apps: Fix CameraNextMod's power shutter not working

Interested users can go ahead and install the SlimSaber/SlimLP ROM on their OnePlus One, using the step-by-step guide posted below.

IBTimes UK reminds readers that it will not be held liable for any damage to device during or after the custom ROM installation. Users are advised to proceed at their own risk.

Prerequisites

The instructions given in this guide are meant for the European variant of OnePlus One (aka bacon) only. Verify device model number by navigating to Settings > About Phone.
Ensure the phone has at least 80% battery charge to prevent unexpected device shutdown (due to battery drain) while installing the ROM.
Back up data and settings using a recommended custom recovery tool, like ClockworkMod (CWM) or TWRP, as it creates a complete image of the existing phone setup. In Recovery, choose Backup and Restore and tap Backup.
Verify correct USB drivers for the phone are installed on the computer (download OnePlus One USB drivers).
Enable USB Debugging mode via Settings > Developer Options (if running Android 4.0 or above) or Settings > Applications > Development (if running Android 2.3 or earlier).
Ensure that the device is rooted with CWM recovery installed and its bootloader is unlocked.

Downloads Required

Android 5.1.1 Lollipop SlimSaber aka SlimLP ROM for OnePlus One

Google Apps or Slim-Gapps

Steps to Install Android 5.1.1 Lollipop on OnePlus One via SlimSaber aka SlimLP ROM

Step 1 - Download Android 5.1.1 SlimSaber aka SlimLP ROM for OnePlus One on the computer

Step 2 - Connect and mount the phone's USB mass storage on computer with USB cable

Step 3 - Now, copy the downloaded SlimLP ROM zip file to the root folder on the phone's SD card

Step 4 - Power off the phone and disconnect its USB cable from computer

Step 5 - Boot the device into Recovery Mode by pressing and holding Volume Down and Power buttons together

Step 6 - Once the phone enters CWM Recovery, perform a full data wipe task by clicking Wipe Data/Factory Reset. Use the Volume keys to navigate between options and Power button to select an option in the Recovery Mode

Step 7 - Perform Wipe Cache Partition and wait until the process completes

Step 8 - Perform Wipe Dalvik Cache as well. To do this, go to 'advanced' option and then click Wipe Dalvik Cache. This will help in preventing boot loop issues or any boot ROM related errors during firmware installation.

Step 9 - Then return to the main recovery menu and choose Install Zip from SD card.

Step 10 - Click Choose Zip from SD card. Use volume keys to navigate to the SlimSaber/SlimLP ROM zip file that you copied earlier to your phone's SD card and choose it by tapping the Power button. Confirm the ROM installation on next screen and the installation process will begin.

Note: Repeat Step 9 and Step 10 to install Google Apps (Gapps) as well.

Step 11 - Once the ROM and Gapps installation completes, go to "+++++Go Back+++++" and select Reboot System Now in the Recovery menu.

The phone will now reboot and the first boot may take about five minutes to complete. So, please be patient.

Your OnePlus One is now running the latest Android 5.1.1 Lollipop via SlimSaber custom ROM. Go to Settings > About phone to verify the firmware version installed.

[Source: XDA]