We here at Goproforums always goes the extra mile and We thank Ifti for bringing some thing so simple , for us to do, hoping this video will help you decide how to go about your firmware, but also remember we take absolutely no responsability for your Actions Any questions ask. thanks @Ifti for anotehr good video.

FISH

 

As we would suspect, GoPro are discouraging downgrading firmware:

https://gopro.com/support/articles/downgrading-your-firmware

In fact, there's no ill effects by downgrading - it all works fine, as demonstrated in the above video.
However, you need to think about how long you will stay on the v1.50 firmware though. Soon they may have more firmware offering new features - which is more important to you? Using third party batteries or having new features and bug fixes?.......

 

Gopro does not offer outdated firmware and will Deny all users factory to the recent, only what is posted up at the site. If you hose the cam, you are out of warranty. best to be advised, at your own risk. a $5.00 battery vs a gopro or higher price battery all come from one place, Mother Earth, whatever works for you stick with it? soon down the road Gopro will lock older firmware out. and soon down the road they will be charging for apps into the camera to work like timelapses, nightlapse etc. once they get things rolling that is the future and already done with a number of camera's

FISH