PS3 OFW 4.00 Service mode?

I apologize because this question has already been asked (in canada) as in http://ca.answers.yahoo.com/question/index?qid=201...

but i really need to know the answer. The question if you cannot see it is, by searching google and all of the info found on it, everybody in service mode beyond 3.56 FW cannot get out of it being on a higher FW. That being said, if I were to enter service mode in OFW 4.00 and downgrade to 3.55 or below (which i can i already looked at OFW upon manufacture date/model), would i be able to get out of service mode once i downgraded to that FW? Please i need to know a surefire answer. His question was answered with a yes but everywhere else i see says you need a flasher hands down. Thank you for your time.

BTW i have slim model CECH-2501B