How can I revert to an earlier firmware version?

[Android Central Question]

How can I "undo" the most recent update for the Galaxy S9? Is there a way to download and install an earlier version without EVER being prompted to update to the newest version? My Galaxy S9 was forcibly updated yet again. Normally not a huge issue, but I absolutely loathe the new GUI, and my battery now has quite a short lifespan. I'd love so much to get whatever the latest version was right before the January 2019 update. As I said, it's a Galaxy S9. I have Verizon, and bought the phone in early Spring of 2018. Will I have to root my device? I've heard of this term but really don't know what this entails. Please please please help me get this awful update off my phone.

 

[belodion]

It may be possible, but it would not be easy, and you would probably need help and advice from members. I recommend joining as a member if you wish to take this further. In the meantime I'll move this to the S9 forum.
To register: https://forums.androidcentral.com/showthread.php?t=409154

 

[mustang7757]

How can I "undo" the most recent update for the Galaxy S9? Is there a way to download and install an earlier version without EVER being prompted to update to the newest version? My Galaxy S9 was forcibly updated yet again. Normally not a huge issue, but I absolutely loathe the new GUI, and my battery now has quite a short lifespan. I'd love so much to get whatever the latest version was right before the January 2019 update. As I said, it's a Galaxy S9. I have Verizon, and bought the phone in early Spring of 2018. Will I have to root my device? I've heard of this term but really don't know what this entails. Please please please help me get this awful update off my phone.

You need to download last Oreo firmware and use Odin then never touch that update button and be stuck on same security and no improvement device.