Prius Prime Smart key fob replacement

I accidentally damaged one of my prime smart key fobs. Not 100% sure how I did this or what went wrong, but I know it's my fault. I had already voided the warranty on it by dinking with it for a project I'm working on. I didn't modify it much, I took out the battery and soldered red and black wires to its battery contacts. I also soldered very tiny wires to its lock button, AC button and its led.

After some reverse engineering work, I figured out that the buttons and led on it each have two contacts to them, but one of the two is always a ground wire. That's not important now.


I had a voltage surge on my device and I'm guessing a blast of higher DC voltage went onto he tiny fob board. As of now, the fob's RF and buttons no longer work. But, the NFC mode still works to start the car if I hold it near the PTS button and press the brake. This makes me think the damage is not too bad.

If I can't fix it, it's not totally useless, it still would be fine as a backup unit with a blade key and can still start the car in batteryless mode.

However, what would it take to get a replacement key? I can get a "blank fob" for about $100 used, $300 new. A locksmith wants between 100 and 200 labour to program it to my car. I saw some youtube videos on different older smart keys, and it didn't look too hard to add a key to the car's computer, using some serial cable and software on a laptop. Is this possible on the prime? I'd rather spend $100-200 on this software so I can take care of this myself if it happens again.

If I get a key from a junkyard, can I use that? How can I "blank a key" that's got data on it already. What would you do in my situation...ya know besides quit screwing around with my car's technology, because I'm too commited and to far to quit doing that now.