Car: 2017 civic ex with sensing
Problem: Wonky infotainment after replacing battery. It comes on but is glitchy. Cannot get into the radio. when I press the audio button it says audio power off, but no way to turn on or the screen goes blank. The backup and side cameras are black screen, no audio controls. I got the car play up once but audio played out of phone speaker. volume doesnt work. settings menus don't fully load when pressed.

I've tried: pulling the radio fuse for a hard reboot, disconnecting the battery for a hard reboot. holding the power button on the radio for a soft reboot. it all reboots to the same crappy situation. Cannot try a factory reset cause I can't get into the settings due to the glitch.

No more warranty.
Hoping someone will chime in with the cure.

I will stop by the dealership in the next few days in hopes they can just fix it and not try to tell me its going to be thousands of dollars to install another shitty head unit.

Quick update:
I went by the dealer and they wanted $180 to mess with it and probably tell me its gonna be $1500+ to replace. So i drove to the junk yards and talked to some yard homies who told me to pop it out to see the model number. So i youtubed how to pull the thing out and it was easy. Got the model number and found a used replacement unit at a honda dismantler about 30 miles away for $100, they have 2 in stock with original vins to obtain codes. I will swap mine out and try to get the code from https://radio-navicode.honda.com updates to come.

Problem solved!

I went to the junk yard and bought 2 used head units (perfect model match) just in case. They were $100 each. Something told me to buy both. I tried the first one and the honda website spit the code right out. I installed it (very easy), and the code worked, and the system is 100% functional. I decided to obtain the code for the unit that I did not use and the vin didn't match the serial (glad I bought 2). Bottom line is that if your radio is still messed up after all the hard and soft reboots just start calling the honda dismantlers (junk yards) and see if they have your model of unit. Make sure you get the correct vin number of the car it came from and you can get the code. I know I am the only one who wrote in this thread, but credit is due to the clues I got from this forum as a whole.

side note: I salvaged my screen which was perfect and put it on my replacement radio, cause the junk yard radio screen was scratched. this was also very easy.

Glad you got it figured out

Nice work!

Thanks guys. I hope this post helps some folks out.