Nice! I've had very good luck with most (not all!) of the Biqu boards I've used, at least in printing space. I've also had great (100%) luck with warranty claims.

If you're really launching into this thing, then: I came across a set of ifixit sorta-teardowns[1] on a Cricut machine earlier today. It showed what appeared to be relatively-small 4-wire motors (often with gear trains shown, which does matter), which strongly suggests that 2-pole steppers are being used. That's easy enough.

The TMC5160 on the Biqu Rodent seems like a strange choice for this job: The 5160 is a high-current dude that's meant more for grunt than precision. The availability of grunt doesn't necessarily outlaw the ability to be precise, but it may not necessarily represent an ideal set of tradeoffs.

Perhaps a board with smaller stepper drivers may be better-suited. After all, if the motors are small and they've got gear reduction on their outputs, then: They don't need much grunt to make the bits move move in predictable ways.

The photos also showed that some/many/all of these motors have optical encoder wheels. Perhaps they're optional in a build with a custom brainbox (we do usually get along fine without that kind of feedback in printing), but their presence is certainly interesting.

And: There were nowhere near enough connector pins shown on what was described as the motherboard for all of this stuff to happen. That's concerning.

It all combined to strongly suggest to me at that time that the ICs that drive the motors might be located elsewhere in the machine, and that there may also be some servo feedback that happens in stock form.

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That concludes my brain-dump on what I think I know about Cricut machines. Take it as you will. :)

And: The FluidNC Board Mapping Wizard is an amazing tool. I will save this for future use. Thanks!

[1]: https://www.ifixit.com/Device/Cricut_Maker