That was my thought .... when I first did mine about 18 months ago.
You will also get a fright when you do your first firmware flash and get a constant BEEEEEEPPPPPPPPPPP with Error on the screen ..... This will especially happen when you go back to the original firmware, as you need both the Epprom and Flash Files to get her to work again ....
I have done it many many times.... I have all the original files here and they are also on the
9xforums.com site. You are in safe hands there.... I used to help a heap of people on that site, since I got rid of my 9x Tx I have not had much to do with the forum or site content additions. I still have access to the admin editing capability on the wiki pages for 9x as it is a community effort.