Having the same issues on a J1900 device. Only CDRom device is not found after kernel booted.
That’s the device I have: http://hamsing.com/product/html/?39.html
I get exactly this error message: http://forum.mikrotik.com/t/putting-iso-on-usb-stick/18557/1
Any hints ?
If you folks have a alpha image, let me know. As I don’t yet use this device, I can test around a lot (And, working from home, I can always take 5 minutes to test it out).