At this point tbf I think this protocol (UF2) that MS collaborated on is the easiest I've seen:
https://makecode.com/blog/one-chip-to-flash-them-all.
Just drag and drop, or detect the specific mass storage, or save to location from browser. Super easy.
Which, after checking that Casio mod site...is exactly what they use! So never mind ha ha. But the blog post on UF2 is certainly worth a read; it's just so simple, it's brilliant.
