BT modem stops working after driver update

[sfriedberg]

I have a Z60m with internal Bluetooth modem which has been working fine for a year. I recently upgraded the Bluetooth drivers and firmware from Lenovo's support site, and this has caused the modem function (and the modem function only) to stop working. Running Windows XP w/SP2.

I definitely don't have the Microsoft BT stack enumerator. bth.inf and bth.pnf have been renamed, and the driver version on the Bluetooth Bus Enumerator matches the Lenovo stack: 5.1.0.2100.

Device Manager reports Thinkpad Bluetooth with Enhanced Data Rate, Bluetooth Modem, Bluetooth Communications Port, Bluetooth Hands-free Audio, and Bluetooth Stereo all are working properly and have driver version 5.1.0.2100 installed. Bluetooth Configuration > Diagnostics reports the Thinkpad Bluetooth with Enhanced Data Rate is working properly with firmware 2.1.211.299 installed.

The BT device successfully discovers a variety of other devices nearby, it pairs successfully which the other devices I control, and the Audio Gateway function definitely works.

However, when I try to dial out using the BT modem, immediately I get error 633: device already in use or not configured properly, and the modem log file contains the following:
03-31-2007 12:28:15.015 - File: C:\WINDOWS\system32\tapisrv.dll, Version 5.1.2600
03-31-2007 12:28:15.015 - File: C:\WINDOWS\system32\unimdm.tsp, Version 5.1.2600
03-31-2007 12:28:15.015 - File: C:\WINDOWS\system32\unimdmat.dll, Version 5.1.2600
03-31-2007 12:28:15.015 - File: C:\WINDOWS\system32\uniplat.dll, Version 5.1.2600
03-31-2007 12:28:15.015 - File: C:\WINDOWS\system32\drivers\modem.sys, Version 5.1.2600
03-31-2007 12:28:15.015 - File: C:\WINDOWS\system32\modemui.dll, Version 5.1.2600
03-31-2007 12:28:15.031 - File: C:\WINDOWS\system32\mdminst.dll, Version 5.1.2600
03-31-2007 12:28:15.031 - Modem type: Bluetooth Modem
03-31-2007 12:28:15.031 - Modem inf path: oem18.inf
03-31-2007 12:28:15.031 - Modem inf section: Modemint
03-31-2007 12:28:15.031 - Matching hardware ID: {95c7a0a0-3094-11d7-a202-00508b9d7d5a}\wcbtmodem0
03-31-2007 12:28:15.031 - Opening the modem device failed with error 000005aa

I suspect the problem may actually lie with the BT comms port rather than the modem, but there is only a single driver file: btport.sys and it's the right Lenovo/Broadcom version. That would be consistent with the 0x5aa error and with the fact that of all the BT functions, the communications port is the only one for which the New Hardware Wizard can't automatically find the driver and I have to "help" it.

The problem is not in either the network connection settings or the device I want to use as a modem (Audiovox SMT 5600), since I can use both successfully when I tether the phone to computer with a USB cable.

After my first six hours trying to get things working again. I attempted a Windows XP system restore in safe mode to put things back to before the upgrade. The restore claimed to complete, but it did not fix the problem. Over the last week, I have probably put in another 20 hours with repeated uninstall, purge registry, reboot, reinstall cycles. The system is now stable and apparently clean but the BT modem is still not functional.

I am not going to do a full system recovery/reinstall. The convenience of working BT is not even close to the inconvenience of reestablishing 14 month's worth of system state. Any other assistance or suggestions would be welcome at this point.

edit: corrected a typo in driver revision number

[RealBlackStuff]

Have you tried physically removing the BT daughtercard, reboot without it, turn off, reinsert card, and let XP auto-install it again?

[sfriedberg]

No, that didn't occur to me (although I did power off the machine). I will give that a try when I next shut down (using the system now) and report back.

[sfriedberg]

It took me a while to find the BT module, but that didn't solve the problem, unfortunately.

[sfriedberg]

I was able to get the Bluetooth modem functionality back again by purging the Lenovo/Broadcom stack entirely and reinstalling the Microsoft stack. The Broadcom stack has far more features, but they don't do me any good when not working.

So, this is pretty clearly a driver issue. Why it struck my particular Z60m installation is beyond me.

By the way, if you are using the Microsoft stack and attempting to enable a Bluetooth service on a discovered device, for example dial-up networking (DUN), and get a Bluetooth Service Error of "Access is denied", change the logon property of the Bluetooth Support Service. I found mine had been installed with a user of NT_AUTHORITY, which I did not recognize. When I changed it to logon as Local System Account, the access denied nonsense went away.