It seems that CFMOTO is not interested or intentions for providing any rebuild parts for their brake calipers. This is a shame because brakes are a maintenance item, and there should be rebuild kits made available for them.
The boots material is extremely thin and easily torn, so be careful.
In my hunt for slide boots, I came across two that can be made to work with a little effort.
Duralast H16011
Wearever 18019a
In both cases, the bottom portion needs a size reduction to fit into the caliper. I accomplished this by using a table sander to thin the base and reduce the circumference. It fit pretty well after that bit of fiddling, and is of much better quality than the OEM boot.
$4 buys a four pack.