This is just the first step…

PS: take by crap phone camera, not screen capture, sorry about the bad image quality.

I find last time I can not insmod fbusb.ko to raspberry pi is because a stupid issue…raspberry pi already have a module named usbtest.ko, it is using same USB VID/PID. Ye, I can not afford that USB ID cost so I just use the chip CY7C680 default VID/PID, that cause the conflict and kernel taint… 🙂

Now it works…just replace the usbtest.ko in /lib/modules/4.19.50*/kernel/drivers/usb/misc/usbtest.ko with fbusb.xxxx.ko, in /lib/modules there are three usbtest.ko, not sure why there are so many of them…for simple, replace them all 🙂

Then reboot, you will find /dev/fb1, and write 16bit bmp to it, display normal.
It’s done. :p

PS: sudo FRAMEBUFFER=/dev/fb1 startx do not work..need deep dig into it.