Intel says it's a one way trip, though often there's a way back by the end of the episode. Quoting from the release notes:
"There is a fifth dimension beyond that which is known to man. It is a dimension as vast as space and timeless as infinity. It is the middle ground between light and shadow, between science and superstition, and it lies between the pit of man's fears and the summit of his knowledge. This is the dimension of imagination. It is an area we call the BIOS Revision 0035 Zone."
The docs say no. Did you actually try it? If you have a Ivy bridge CPU then 0035 is a must have.
There may be tricks to workaround the downgrade protection, but I think that the best thing is to wait for the repaired 0035 BIOS... Hopefully they get everything correct this time and not introduce other bugs in the repair process.
