ZVW35 (Prius Plug-In) ECU Swap Possible?

I have a "customer's" (friend that I'm trying to help out) Prius here, that I am trying to help them fix. Firstly the engine was blown. That was prior taken care of, but the car refused to run. I now have a whole slew of codes, U0100 being one of the most concerning. I took the hint of 'ECU not responding', and disassembled the ECU itself (I am mainly an electronics technician, mechanic work is my 'hobby' and love/hate passion). Much to my dismay, I found the culprit -- I almost don't even want to show you pictures. I cleaned it up, and while it looks like a transistor 2SB1721 is damaged, the rest of the ECU seems okay from a cursory test. I can't find the transistors genuine, so I plan to go to a pick'n'pull and snag an ECU to use as either parts or complete swap (I can get one fairly cheap, perhaps 30-40 bucks).

I considered doing a full swap of the ECU, I have TIS/Techstream and the knockoff Xhorse MVCI/J2534 to aid. However, I ran into this sticker on the ECU's chassis, and am wondering if it's safe to just swap out the ECU with a used one. My concern is if the vehicle is like larger laser printers, and it stores multiple copies of its' firmware/ROM on various boards, and when one is swapped it has the potential to overwrite the 'original' ROM remaining in the car from the 'donor' part (ECU). Is it possible/safe to use a used ECU and program it as needed, and this sticker is just a Toyota 'oh no use OEM new genuine Toyota parts only or your mother will slip and break her back' scare'em'up tactic, or is it something that absolutely NEEDS to be adhered to? I can always swap the ROM chip/s from the original ECU as needed, if that is necessary and the original does have too extensive damage to salvage.

Photos are provided below (1-3 of the damage before cleaning, 1-2 of the damage after cleaning, 1 of the warning in question). The damage was cleaned with isopropyl alcohol, then a very active flux (Chipquik brand), stripping the old solder and replacing it with new eutectic Kester 44 lead-bearing solder. Note the flux is not removed in the 'after' pictures yet. I also have an ultrasonic cleaner if the damage is not thoroughly cleaned enough, but I don't want to resort to that unless I have to.

Thanks for any advice you can provide!

 

Thanks for the advice! I'm gonna try to find one at my local junkyard, and I see there's a couple on ebay for fairly cheap as well.

 

Okay, so I dropped a new (used) ECU into the vehicle, and it does seem to at least read that. I have to ask, what are my options for flashing this thing properly? I have at the moment a knockoff Xhorse J2534 device and an old copy of TIS that I've been using. Is there any way to make this happen at home, and if so what would I need if what I have isn't sufficient? My copy of Techstream won't connect to check for calibration files, is there still a way to 'rent' the software like there used to be and will it do ECM updates? Any ideas what a dealer would charge?

As for the cause of the corrosion, water definitely got into the ECU area. I don't expect it to happen again, so I wouldn't worry that.

 

Just to update here, I fixed the issue by simply replacing the ECU with a used ECU and rewriting the VIN to the proper VIN with Techstream 12.10.019 (cracked) and a knockoff MVCI connector. No need for all the nonsense I was trying.