Christian,According to this PDF, if you are getting "Waiting for root file system" on bootup, IT821X IDE support needs to be hardcoded into the kernel, as opposed to a kernel module. CONFIG_BLK_DEV_IT821X=y. Changing this parameter works for me on a later kernel.
http://www.compactpc.com.tw/drivers/ebox-2300SX/Vortex86SX_Linux_HowTo.pdf Sean Lazar