Yeah, but you had fastboot a minute ago???
Does the charging light go on when you plug it in?
Leave it charging in any case.
Have you tried another Type C device on this cable?
You're saying that Windows takes no notice, no "bongs", no error messages when you plug it in?
You don't see a VID/PID of 1f3a/efe8 in UsbView?
Code:
Device Descriptor:
bcdUSB: 0x0110
bDeviceClass: 0x00
bDeviceSubClass: 0x00
bDeviceProtocol: 0x00
bMaxPacketSize0: 0x40 (64)
idVendor: 0x1F3A
idProduct: 0xEFE8
bcdDevice: 0x02B3
iManufacturer: 0x00
iProduct: 0x00
iSerialNumber: 0x00
bNumConfigurations: 0x01
Have you tried a long ~30 second power press?