Prius Plug-In ECU Swapping Question

Hello again. I recently replaced an ECU due to water getting inside it, and corrosion building up along the bottom. The new ECU is readable by my old copy of Techstream and knockoff adapter, but I don't have anything to flash it with. Dealerships have given me the run-around and jerked me about (oh I don't know if we can reprogram that, let me direct you to x, give me your number and we'll call you back - and never doing so, i don't know what we'd charge, etc), and I don't want to drop the 500 bucks plus 65 to rent Techstream and buy the hardware adapter. I do, however, know a good bit about microsoldering (component-level technician specializing in amplifier/laptop/phone repair). I was wondering, would I be able to get away with swapping the EEPROM chip on the ECUs? Anyone have any thoughts on that idea? The original ECU would probably be repairable, I don't believe it's actually damaged; but I don't want to throw a partially water damaged board back in a car, even if it was cleaned up.

Thanks for any input you have to offer!

 

Okay, I come bearing news. I finally gave up and tried it. I have my issue(s) solved, and I'm here to answer my own question for anyone that may find this later on.

1.) I tried to swap the only EEPROM IC I found, an 8-pin IC labeled "RH86". The ECU did NOT like that, it threw an error code pair, P0606/P060A (Internal PCM Fault and Internal Control Module Monitoring Processor Performance, respectively). So, I swapped back. The ECU part numbers were identical, so that means something else in these ECUs either contains information, that was not swapped over, or the IC that was swapped contains information about the rest of the ECU's individual parts perhaps a CPU ID or serial number, etc). The IC is shown in the picture I have attached (note this is under a stereoscopic microscope, for an idea of scale it is about the length of a grain of rice).

2.) I restored the new (used) ECU to stock. The car was reading as the 2013 Toyota Prius the replacement ECU came from, so I wrote the VIN using Techstream 12.10.019 and a knockoff (clear) MVCI adapter. After this, everything was okay. I did not need to reflash the ECU at all, it worked with the immobilizer and everything.

So, no need to get as in-depth as I tried to. Everything works out fine, just rewrite the VIN to the new ECU (try to get the same year or newer at worst, and obviously ensure the part numbers are the same) and you're set.

 

Always happy to share knowledge, I am where I am today only because of others that are the same way! And it's not too impressive, as it is. SMD components aren't too bad to work with; at least not pin-circumferenced things like this. When you get to pins that are not directly accessible, like BGA components, that's where the REAL impressive stuff starts. This stuff, you can just take a glorified heat gun and heat up until it's sufficiently attached, and touch up with an iron. BGA, you have to really know what you're doing to get a sufficient outcome.