"Invalid payload length" on WCH-Link CH549 at ProbeInfo response payload

[rowanclarke]

Running wlink -vv regs gives the following output:

13:15:09 [TRACE] (1) wlink::usb_device::libusb: [src/usb_device.rs:118] Device: Bus 002 Device 003: ID 1a86:8010
13:15:09 [DEBUG] (1) wlink::usb_device::libusb: Serial number: "0001A0000001"
13:15:09 [TRACE] (1) wlink::probe: [src/probe.rs:196] send command: GetProbeInfo
13:15:09 [TRACE] (1) wlink::probe: [src/probe.rs:177] send 810d01 01
13:15:09 [TRACE] (1) wlink::probe: [src/probe.rs:187] recv 820d02 0201
Error: Invalid payload length

The error arises from the ProbeInfo response here, where there must be at least three bytes in the payload but my payload only contains two bytes [2, 1]. It then seems as though only the first two bytes are being used.

What should the payload of three bytes look like if only the first two are going to being used?

Thanks,
Rowan