For anyone finding this looking for info, here is some stuff I could figure out:
- That's a knockoff RCMx86 sold by Aliexpress and the like. It has a different pinout.
- It most likely does not support UF2 mode, at least I couldn't get mine into it. The reset pin seems non-functional.
- Based on the diagrams given by the Chinese manufacturer, I don't think it has a USB strap option.
Here is a pinout I found online, supposedly from the manufacturers of this knockoff:
EDIT:
I just realized mine is an EVEN WORSE KNOCKOFF than yours! It doesn't even use a SAMD21 chip! So maybe yours does have UF2 mode. Here is the chip I have in mine that I thought was the same as yours:
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