Sorry for replying so late, but I was on vacation.
@maulwurf:
> can u tell me which bios u modified.
>
>i am searching for someone who is able to modify the firmware of the wirless card - in this case the intel >2200bg could the system be shown as original ibm wifi card?
>
>in 2nd case tell me how you modified the bios in any way plz.
I think there is a kind of misconception you have: The BIOS modification just lets the Thinkpad think it knows that specific kind of WLAN adapter. Every PCI card has so-called PCI IDs and the ones IBM sells are hard-coded into the BIOS. If a non-IBM card is detected, the BIOS stops with an error code. Modifying the BIOS is moot, since setting the magic CMOS bit with the no-1802 program disables the check anyway. The only difference between the two methods would be if you cleared the CMOS completely (e.g. if the CMOS battery fails), the computer would fail to work if you used the no-1802 method. Modifying the BIOS is a complicated and dangerous task and I will give no details.
Modifying the BIOS does not influcence the WLAN card whatsoever. There is no way (at least not documented) to "modify the firmware of the wireless card", most likely, it does not even have a firmware.
None of these methods does provide the display of the WLAN activity LED with non-IBM 2200 BG adaptors, since Intel delivers different types of hardware for different Centrino vendors. The differ in PCI IDs (causing the 1802 error in Thinkpads) and in WLAN activity activation (an optional feature of the Mini-PCI standard).
@Candid:
Maybe the section above does clarify what happens with regard to hardware and BIOS startup. After that, Windows starts up and the drivers take over. The LED problem seems to be unrelated to drivers. With different hardware (e.g. non-2200BG, such as Atheros a/b/g cards), even the LED might work.
What poses a little problem is that a) Windows b) Intel and c) IBM all provide drivers (plus utilities) for the same type of card and the different online update procedures (Windows Update, IBM Access, Internet download) can interfere. IBM for example provides the Intel drivers but uses an own utility for WLAN selection and parameter changes (IBM Access Connections). Thus, three types of utilities can interfere: IBM Access Connections, Window's own WLAN utilities (even more so with SP2) and Intel's utilities if you ever installed their 2200BG drivers. The IBM utility does check for the driver version numbers and refuses to work with versions it does not know (much like the BIOS). But: the IBM drivers do in fact work with a non-IBM 2200 BG card (since they are plain Intel drivers sans the Intel utility). Every software function works, including enabling and disabling WLAN.
As for modifying the BIOS: yes, the problems you describe are exactly the ones you can expect, since the format IBM uses for their images is compressed. And as I have written, the whole process is utterly useless, since setting the magic bit by no-1802.com is essentially equivalent. No other problems than disabling the 1802 error can be achieved by modifying the BIOS, sorry.
So, my point being is: Use the no-1802.com, it will fix all that is fixable. Use the IBM drivers and utilities (but be sure to download the newer versions). IBM's point of view is that they tell everyone on their website that only IBM hardware is supported, so "nothing is wrong" (TM).