Can't upgrade i4 with custom 4.1

[Cokeman]

I am trying to upgrade my i4 from 4.0 to a custom 4.1. Every time I try, I get either error 21 or 1600. At which time it takes 3-4 tries to get itunes to restore to 4.0.
I have every shsh available for the iPhone 4. All saved on my pc.

How can I get it updated to 4.1 so I can keep my baseband?

Windows 7 pro 64bit
iTunes 10.2

[Simon]

You need to enter pwned dfu with pwnage tool or redsnow before you can restore to a custom firmware.

[LinuxFP]

Or you can try TinyUmbrella

[Cokeman]

You need to enter pwned dfu with pwnage tool or redsnow before you can restore to a custom firmware.

How can I do that with a iPhone 4 & a Windows PC? I tried the latest redsnow doesn't work.

Or you can try TinyUmbrella

Tried doesn't work. I still get the errors.

Do I have to have a mac to keep my baseband?

[Simon]

what errors?

[Cokeman]

i get error 21 or 1600 (in iTunes) every time I try to update to 4.1 or just restore to 4.0. I got it to work 1 time after about a hour. That got my phone back to 4.0 & usable again.

Upgrading in recovery mode causes error 21
Upgrading in dfu causes error 1600
With or without Tinyumbrella running.

[Simon]

You need redsnow 0.9.6rc8 and a copy of a regular 4.1 firmware. You open redsnow, point it to the 4.1 regular firmware. Choose the option to just enter pwned dfu. Then shift restore to the custom one in itunes.

[Cokeman]

x98car, That worked perfectly. Thank You.

[Simon]

No prob