How to update LG Optimus G to Android 6.0 Marshmallow using custom ROM

LG Optimus G is now a three year old device, which means it will not get Android 6.0 Marshmallow update officially. Which is why, custom ROMs have a definite larger hole to fill, and guess what, the developers know this: a Android 6.0 Marshmallow based custom ROM is already available for the LG Optimus G, the grand-daddy of rockstar device we know as LG G3.

In many ways LG has to be thankful to Optimus G for it made a definite impact in increasing the company’s brand name as Android OEM. Before LG Optimus G, LG only struggled, but after it, it was able to get some much needed fan following, that gained more traction with LG G2’s success. The LG Optimus G, Nexus 5 and LG G3 followed and helped LG create an aura that you sit up and take notice of company’s next product more seriously than ever.

So, Optimus G is a special phone for LG, just like Galaxy S and S2 were for Samsung.

Which is why it’s great to see a a Optimus G Marshmallow update coming up, even though it’s unofficial.

The great thing is that almost everything is working, and you don’t have any serious drawbacks, which could easily have been. The stock camera isn’t working right now, but included in the ROM is Google camera app, which is working perfectly fine.

Similarly the AOSP browser from Marshmallow update force closes when you hit a download link, bu that’s not a cause for any other browser, so just install the Google Chrome or any browser and you are good to live with it.

So, let’s see how to install the LG Optimus G Marshmallow update.

Downloads

Marshmallow custom ROMs
- ROM 1 — Link | File: aosp_geehrc.zip (234.31 MB)
- ROM 2 — Link | File: Nitrogen-OS-271015-geehrc.zip (224.2 MB)
  → Download any one ROM from above, and the Gapps file below.
Google Apps (Gapps) — Link

Supported devices

LG OPTIMUS G, model E975 (codename geehrc)
Don’t try this on any other device than the one having model no. specified above.

Use the Droid Info app, to determine the codename of your LG Optimus G. If it is geehrc, then it should be compatible with the 6.0 custom ROM we have here.

Warning!

Warranty may be void of your device if you follow the procedures given on this page. You only are responsible for your device. We won’t be liable if any damage occurs to your device and/or its components.

Backup!

Backup important files stored on your device before proceeding with the steps below, so that in case something goes wrong you’ll have backup of all your important files.

How to Install

Required: You will need to have TWRP recovery installed on your device to be able to install Marshmallow custom ROM and Google Apps (Gapps). Check out our page on LG Optimus G TWRP recovery for flashing Gapps.

Download the Marshmallow ROM (any one of the two above) and Gapps file from above.

Connect your device to PC and transfer the ROM and gapps file to it. Disconnect the device then. Remember the location of the files.

Boot your LG Optimus G into recovery mode. If you are rooted, you can use Quick Boot app from play store. To manually boot into recovery mode, do this:

Power off your device and wait for 5-10 seconds until the device is fully switched off.
Press and hold Volume Down + Power button together and release them as soon as you see the bootloader screen.
Press Volume Down button twice and then press Power button to boot into recovery mode.

You will enter recovery mode soon, and should see TWRP recovery. If you see 3e recovery, then you need to install TWRP recovery for this.

[Optional] Once in TWRP, create a backup of your device. Tap on Backup, and then select all the partitions for back. Now do the swipe action at bottom to start creating a backup for emergency cases. This backup is really a lifesaver!

Do a Factory Reset. On TWRP’s main screen, tap on Wipe, then advanced wipe, and now make sure you have selected these partitions: dalvik cache, data, system and cache. Then do the Swipe action at bottom to confirm it.

Unmount System now. Use the TWRP’s mount menu, and then deselect the System from there, so that it’s not mounted while we flash the ROM.

Now, install the ROM file. On TWRP’s homescreen, tap on Install, and then locate the ROM file and tap on it. Then do the Swipe action at bottom to begin flashing the update.

Tap on Home button to go back. Now, install the Gapps the same way you installed Marshmallow ROM on your LG Optimus G.

When it’s done, tap on Reboot system button to restart the device.

That’s it.

Let us know if you need any help with this via comments below.

And btw, you have to thank some people for this, who made this possible: Kevinjoa, Abhinav2, and other Optimus G developers, who contributed their code and knowledge to this.