Aftermarket Head Unit Switching Off On Bumps In The Road

I plan on re-soldering all of the connections that connect the unit and leave solder in between the connecting wires and soldering over the exposed wire and covering it with a few layers of electric paint. Is this the best way to solder wires together?
Also could it be anything else? It's an alpine cde-133bt with a failed firmware update. (No idea how to fix that either, I do plan on getting a new radio because I pressed one stupid button thinking it could update through a connected iPhone, lol.)

 

I've installed about a dozen headunits in a dozen different vehicles, I've never soldered, I've always used butt-splices. I've never had a wire pop off *knock on wood*

Just my 2 cents!

 

Well, I re-soldered every connection and I believe my mistake was using too much solder and not connecting the wires properly by taking one wire end and making sure it was connecting with the other wire end as many times as possible by interconnecting them better.