Can't flash eMMC of CM4 using another Pi 4

[ll-O-ll]

So I've been trying to flash the eMMC of my CM 4 using another Raspberry Pi 4. I've used the steps outlined at https://www.raspberrypi.com/documentation/computers/compute-module.html#steps-to-flash-the-emmc

Here's what I did:

Connect jumper cable on J2 to disable eMMC boot on the CM 4. Connect J11 USB slave to Pi 4 Power Pi 4 Power CM 4

Here's a picture of my setup:

I expect the CM 4 to appear as a device on the Pi 4 but I see nothing :(

Any steps I'm missing here??