I can remember, while I was doing my second portable, I tested to remove the whole DD, and start the GC with the default BIOS. it obiusly gave an error, but when I connected the qoob pro chip, wich boot up automatically its own bios, it got stuck also, but if you hold the Y buttom of the controller when it is booting, the qoob ignore the optical drive and browse the flashed apps on the chip, I also tested to start the SDGECKO loader apps, being able to run games or homebrew from it with no problems.
so basically this answer to your question.
posible? yes
but obiusly you will need the hardware I mentioned before (qoob pro chip, maybe others also skip the error)
anyway, I noticed some bugs on some games wich boot from SD, the compatibility isnt as good as desired, and is allways nice to have the disc drive or a replacement like the SD interface I saw some time ago on another site.
you also can ask
electric rain about his disk drive replacement.
