thinking of updating 2.2.1 to latest 3.1

[yashraj]

I had updated my iphone 3g to 2.2.1 since then i cudnt use it. I ordered for a turbo sim .Really turbo sim aint workin dat well. I was thinkin of updatin my iphone to 3.1
Is it possibl to jailbreak ur iphone wen ur firmware 2.30 is chnged wen d phone is updated. Precisly can it be used properly without singnal loss