When switching from battery to AC (or back) on my IBM T41 laptop with embedded mini-PCI Cisco WLAN adapter, I lose the IP address after about 30 seconds, and must "repair" to regain it. Using WEP with an open key. When troubleshooting, a PCMICA 340 and 350 card worked fine - then I upgraded the firmware on those working cards to V5.41, and now they both fail in the same way. I'm using Windows XP SP2 to manage the link. When using ACU to manage the link the problem does not happen. When watching ACU status (and while Windows is managing the link), I see the signal drop to zero for a few seconds when I change the power mode - then the address changes to a 169.100.n.n in about 30 seconds. The signal is fine, its associated - its just losing its address and not going back for another one without manual intervention. IBM and Microsoft support has not heard of this before. Hardware problems were suspected at first, but the problem now seems to be following the firmware. Hard to believe I'm the only one to report this problem - but at this point, have seen no other reports of it.
