i need custom 4.2 firmware for iphone 3gs

[slam123slam123]

hi
I have read many posts here, and I did as some members advice
the last thing I need is a custome 4.2 firmware for iphone 3gs
I'll told u what I have done
I bought 3gs with ios 4.2, with new bootrom, with 5.14 baseband
I didn't have the shsh file and I didn't even save it before i start anything on the iphone
I'll mention the steps I did:
1.Open redsnow, choose the firmware 4.2, next, chose install cydia and change the baseband to ipad base band.
2.After finishing I open the iphone and it opened I found the baseband changed to 6.15
3.I read about tethered jailbreak so I decided to restore to 4.1 firmware, and I started it, in the middle I have an error, I searched I found that I can't downgrade the ios without shsh file !
4.I restore to 4.2, official copy, but I got the error 1015, then stuck on recovery mode
5.I used RecBoot to get out from recovery mode but I couldn't
6.I used Tinyumbrella to do the same thing and didn't work
7.I changed the hosts file and the same error
8.I used redsnow I chose the iso 4.2 then next, then get in to DFU mode, then restored, but same error
9.I opened tinyumbrella then open itunes, and changed the hosts file and restored to 4.2, but I got the error 1604 and stuck in recovery mode
10.I tried redsnow again with just boot tethered right now, and same problem
11.I searched again and read some members said u need to restore a custom firmware, but they didn't post the link for that firmware
So I think I need the custom firmware coz it's the last thing I didn't tried ='(
And thanks a lot

[iYeow]

You need to restore to CFW of 4.2.1 ( in your PM box), use redsn0w , browse to stock 4.2.1 and choose only dfu mode. Run itunes , shift + restore to this CFW of 4.2.1
When it finishes, you will either end up in recovery or frozen apple logo ( not sure which one because you have the new bootrom ).
You need to run redsn0w again, choose install cydia ( PT didn't install it for you) and choose tether boot.