[FYT Android Head Units] mastrv:
I bought these heatsinks and "attached" them to the flat factory CPU heat sink with this thermal adhesive tape:

uxcell® 5 Pcs Silver Tone Aluminium Heatsink Heat Sink 100x25x10mm : Amazon.ca: Electronics

uxcell® 5 Pcs Silver Tone Aluminium Heatsink Heat Sink 100x25x10mm : Amazon.ca: Electronics

www.amazon.ca

Amazon.ca

I molded / cut away the heat sink as needed. It just fit under the back cover.

This one shows my SPro/CC2 with back cover removed. You can see the flat heat sink with the indentation. The indentation makes direct contact with the CPU underneath. If you want to get under this heat sink, soldering is required...I did not remove it. You can also see on the back of the cover the protrusion that makes contact with the indentation on the flat heat sink. I replaced the paste there. I don't know if you can tell, but it's actually a little off and doesn't make proper contact with the flat heat sink. I cleaned up the old paste with some rubbing alcohol...actually alcohol swabs...that I had. You can also see on the motherboard where the heat sink for the audio amplifier is. It is just to the left of the large black capacitor and above the power connector and fuse. It's upright and you can see the edge with the white paste on it. I also cleaned up the paste on that and replaced the paste:

This one shows what it looks like after adding the heat sinks. I first cut the heat sinks and then placed the thermal adhesive tape on them and applied them to the flat heat sink. I believe they just fit lengthwise...can't remember. I used a small dremel type tool to cut out what needed to be removed:

I reattached the cover after adding the fans, connecting the fans to the AMP wire and also drilling some holes near the amplifier heatsink on the back cover. I figured that in the corner there wasn't as much circulation and that the audio heat sink could get warm so it couldn't hurt. Notice that I used 2 small 40x40x10 fans, Noctua NF-A4x10 FLX. Can find those at https://noctua.at/en/nf-a4x10-flx. They are a little more expensive but supposed to be quieter and better quality...time will tell. They come with a few connectors to make it easier to attach. I attached them both to the AMP wire. This allows me to turn them on and off through the Amp control setting on the head unit. I turn them off when it starts to get colder. I used silicone to attach the fans. I put a little between the two fans and then filled the channels all around them. They're attached pretty well. If you notice, they line up with the vertical ribs on the back. Not sure if all manufacturers have the same back cover but it shouldn't matter. I made sure the channels were blocked so the air had to be pulled out of the head unit and not from around the fans. I wrapped the electrical connections with tesa tape. Some people used larger fans, thicker fans. You can use other fans that you have available...I didn't want to make too many changes to the back cover:

Here's another shot of the back. You can see the heatsinks through the fans in this image. On my head unit, they just fit and are either very close or just touching the back cover. I also added an external microphone connector...that's what I'm holding:

Oh yeah...the thermal paste I used was some left over Arctic Silver 5 that I had. I figured it was OK since I had used it to attach heat sinks to CPUs on desktop computers. I'm sure there are other pastes which will work fine as well.

Sorry for the long post :)