Recently I tried to update my 2.2.1 N1 to cm-
but it was failed (status 7) then trying to roll-back but it was stucked on the flash triangle start-up.

Well I decided to roll back to 2.1-update1 build number EPE76 as per [TIPS] Stuck On FRF91? Want To Downgrade To Get Root? Click Here! - xda-developers but again it was failed to upgrade cm mode or 2.2.1

Could you please help me with step by step to ugrade to 2.2.1 or cm manually

All options taken and it has been exhausted so far

Many thanks!