Downgrade Galaxy S6,S6 edge, S6 edge+ from Android 6.0.1 Marshmallow to 5.1.1 Lollipop, Yes You Can!

There has been a lot of questions via our contact page surrounding the Galaxy S6, S6 Edge, and even the Galaxy S6 Edge+ Android 6.0.1 Marshmallow updates. Some folks may not conveniently  satisfied how's the Marshmallow performed according to their own experienced. Some may complain about some lag issues, whilst others complained about some of their daily used or important   apps that may not tend to work any longer.

Majority of these folks were asking if they just can temporarily downgrade back their devices from Android 6.0.1 Marshmallow to Android 5.1.1 Lollipop just like the way it was before but may then get back to Marshmallow until it stabilized further.

You can do read these Marshmallow issues in forums and social media.   Now, to keep this post short and straight forward, "Can we really downgrade our Galaxy S6, S6 edge, and S6 edge+ from Android 6.0.1 Marshmallow back to Android 5.1.1 Lollipop?"
The Answer is; Yes you can!
This can only be done on international Galaxy S6, S6 edge, S6 Edge+ plus variants, including the American and Canadian version, but except to those device with built in "locked bootlooader" such as the Verizon and AT&T Galaxy S6, S6 edge and S6 Edge+ models. Devices with unlocked bootloaders can be freely downgrade-able, but those with highly secured bootloader cannot be messed around.

Please do note that this is only applicable for the first Android 6.0.1 Marshmallow update your device received.  This is not advisable to any newer OTA updates that may have a locked-up bootloader. 

Here are the list of Galaxy S6, S6 Edge, and S6 Edge+ with unlocked bootloaders and can be dowgraded from Android 6.0.1 Marshmallow back to Android 5.1.1 Lollipop.

Galaxy S6 models:
  • SM-G920F International Galaxy S6
  • SM-G920P Sprint Galaxy S6 including Boost Mobile
  • SM-G920R4 US Cellular Galaxy S6
  • SM-G920T T-Mobile Galaxy S6
  • SM-G920W8 Bell, Rogers, Telus, Canadian Galaxy S6
  • SM-G920I Australia, Singapore, India,& Latin America Galaxy S6
  • SM-G920K, SM-G920L, SM-G920S Korea Galaxy S6 version
  • SM-G9200 Hong Kong/China Galaxy S6

Galaxy S6 Edge models:
  • SM-G925F International Galaxy S6 Edge
  • SM-G925P Sprint Galaxy S6 Edge including Boost Mobile
  • SM-G925T T-Mobile Galaxy S6 Edge
  • SM-G925W8 Bell, Rogers, Telus, Canadian Galaxy S6 Edge
  • SM-G925R4 US Cellular Galaxy S6 Edge
  • SM-G925I Australia, Singapore, India,& Latin America
  • SM-G925K, SM-G925L, SM-G925S Korea Galaxy S6 Edge
  • SM-G9250 Hong Kong, China, Taiwan Galaxy S6 Edge

Galaxy S6 Edge+ models:
  • SM-G928P Sprint Galaxy S6 Edge+ including Boost Mobile
  • SM-G928T T-Mobile Galaxy S6 Edge+
  • SM-G928W8 Bell, Rogers, Telus, Canada Galaxy S6 Edge+
  • SM-G928R4 US Cellular Galaxy S6 Edge+
  • SM-G928I Australia, New Zealand, Singapore Galaxy S6 Edge+
  • SM-G928F International Galaxy S6 Edge+
  • SM-G928K, SM-G928L, SM-G928S Korea's Galaxy S6 Edge+
  • SM-G928C Southeast Asia Galaxy S6 Edge+
  • SM-G928G Asia, and Latin America
  • SM-G9280, SM-G9287, SM-G928NO Hong Kong, China, Taiwan, Galaxy S6 Edge+

And these are the devices that you shouldn't touch nor messed around when it's have been upgraded to Android 6.0.1 Marshmallow. Doing so will break the bootloader and may ended-up into soft-bricked status.
  • AT&T Galaxy S6 SM-G920A, S6 Edge SM-G925A, S6 edge+ SM-G928A
  • Verizon Galaxy S6 SM-G920V, S6 Edge SM-G925V, S6 Edge+ SM-G928V

How to downgrade the Galaxy S6, S6 Edge, and S6 Edge+ from Marshamallow to Lollipop?

The only way to downgrade the device is to re-install the Android 5.1.1 Lollipop in to the phone.  You can do so by using flashing the official Android 5.1.1 Lollipop stock firmware.

Refer to the following pages according to your phone type:

The process is not that way difficult on some part but just could at-least you return back your phone the way you like it better.

Yet again, don't just take my word on it, you can only confirm this method if it will work or not out of your own.  It's you phone and not mine, so it is still up to you to decide of what to do what can you do about it.