Unlocked 3GS on 4.1 that reboots untethered

I have a 3GS that my niece in US grew out of and therefore sent it over . It had 3.1.2 and is of week 950 -new BR -tied to AT&T. No AT&T here. I upgraded it to 6.0.1 on iTunes11 resulting in a 05.16.07 BB that I only later found was unlockable. I then used sn0wbreeze to get a customised IPSW with iPAD BB - 06.15.00. Later I used cydia for ultrasn0w 1.2.7 and found I could make 'phone calls. However, Safar & Mails were not ok : eMail config took an eternity while Safari after opening would close on its own after a while. Read somewhere that 4.1 was still signed and so tried it. Too many error 14 & 20s apart from a few 1601s. Went back to factory restore on iTunes and after a whole lot of time found I couldn't activate the device. Read somewhere that Apple won't allow activation on a previously JB'd device by saying "Sorry, cannot activate. Try again...". Tried a "Deactivate" with redsn0w and went back to iTunes but with the same result. Tried snowBreeze...6.0.1 IPSW with Shift+Restore . This time the device got into recovery mode with no apparent way out from that. The device thus, was now an iBrick. Tried redsn0w-0.9.15b3 which would accept only 4.1 . I kept getting "Restore Error: found device in DFU instead of Recovery Mode". I think every time I started with redsn0w when the device would be stuck in the Recovery Mode , i'd put it in PWNed DFU Mode through pressing my nail into the Sleep { that button had been chipped off by my good niece } , count upto 6 slowly, press Home , count upto 20, release Sleep, count upto about 12 or so when limera1in would kick in (I think, unless it was "Patching Kernel"). But all to no avail. Somewhere I saw Apple suggesting that when met with an Error 20 during a Restore, perhaps, closing iTunes and reopening it with the device still connected to the USB may help. This seemed to convey that repeated trying was not uncommon in these activities. Therefore, I went back to redsn0w and kept trying with the original 4.1 inspite of "DFU .. instead of .. Recovery" ... I remember selecting "Install Cydia" & "Deactivate" and then unchecking Cydia and "Downgrade BB" (to 05.13.04). To my amazement after about the 4th or 5th try the whole process completed after a huge no of "Please Wait ..." s on the device terminal. The device came back to life miraculously displaying all the icons on the screen. Installed ultrasn0w yet again and the local cellular n/w name was shown on the device. Safar & eMails were pretty much quick enough. And, any time I power off the device with the Sleep button and slide the red bar to power off and then power it on with the same button, it reboots too. Untethered. But if I've got it right, 3GS beyond 940 shouldn't boot untethered after a JB & unlock. Can someone tell me if I've I got this JB, unlock right ? Thanks in Advance. Version: 4.1 (8B117), Model: MC135LL Sl No.: ??950?????? BB: 05.13.04