Absolutely, its like going to a clean slate.
Keep in mind that you don't necessarily wipe the Storage Card automatically, and anything you back up "may" not work with an older application/WM version since the OS might have different registry entries.
Robert
mipoes, on Mar 19 2010, 09:39, said:
Hi all, I have an OCK rom installed to my omnia and i would really try this new 6.1 rom from Khuanchai..my question is if I can go back to 6.1 from a 6.5 rom just flashing again the phone as always..is there any other particular thing i need to do before flashing back to a 6.1 rom?
thank you all in advance for your help

HTC Thunderbolt with
SynergyROM Nighties
Samsung Omnia i910 with
thekevster's M2D WM 6.5 ROM v3 DC22/23563 (retired)
Windows 7 Ultimate 32bit/Ubuntu 10.04 Lucid Lynx dual boot desktop (home)
rooted Barnes & Noble Nook Color
Windows 7 Ultimate 32bit/Ubuntu 10.04 Lucid Lynx dual boot HP NC6000 laptop (home - power issues)
headsets: LG-HBS-200, Motorola HT720