I have 1G iphone was working on 1.0.2 version decided to upgrade to 1.1.4 followed the steps listed in one of the threads...
first i virginised it then instead of upgrading to 1.1.4 i by mistake di it to 2.2.1...tried using iliberty to unlock but somehow didnt work...so i decided it downgrade it 1.1.4...

I uninstalled itunes 8 installed itunes 7.5 then downgraded to 1.1.4 after facing a few probs(error 1601,1045...)...using iliberty i was able to unlock and install installer app...
but now there is NO SIGNAL...Wifi is fine,installer is fine,everything else seems to be fine but theres no signal...
tried everything including fix for no signal,downgrading bootloader...nothing seems to work

it also says sometimes unknown bootloader 3.9_M3S2

these are my baseband info :
modem firmware : 04.05.04_G
bootloader version : 3.9_M3S2
Firmware : 1.1.4

please help and solve my problem...

Do not use iLiberty in this case.

- first download firmware 2.2.1 for iphone 2G to your computer
- use iTunes 8
- put phone in DFU mode and restore with that firmware
- now use quickpwn 2.2.5 to jailbreak/activate and unlock the phone.

You need to read the sticky post on how to put phone in DFU MODE by volkspost

Don't worry ... your phone is OK ...
I have to go now.

I tried updating it to 2.2.1 but cudn't ...
it shows error 1601!!

You must put phone in DFU mode and select firmware 2.2.1.
When you are describing the problem, please tell us exactly how you did it.
It is very hard to help if we don't know HOW you did it.
Simply saying "i tried updating ..." does not mean anything