T40 cmos battery bypass surgery

[plugger2]

My mother has a T40 that was showing the dreaded "Supervisor Password" request at boot time. A few days ago she replaced her main laptop battery with a 9-cell aftermarket replacement, and things seemed to be smooth sailing, until yesterday when this screen popped up. Of course, she had no idea what the password was that was being asked of her.

I suggested removing the new replacement battery and trying a reboot just from the AC power adaptor. There wasn't a great deal of theory behind the suggestion, just eliminating the most recent change to the system. Somewhat surprisngly, that worked -- she was able to boot into XP without being prompted for the BIOS password.

Now, I'm not sure what interaction there might be between the new laptop battery and (I strongly suspect) dying cmos battery, but I think to stabilize the situation one of two things, or preferably both, need to occur:

a) replace the cmos battery with a fresh battery
b) replace the unknown supervisor password with one that is known, or disable the supervisor password protection

Starting with a):

I've read the threads that say that simply disconnecting the old cmos battery prior to replacement will trigger a permanent Supervisor Password lockout scenario, essentially bricking the machine if the password is not known.

Therefore, it would seem a bypass surgery would be required, where the voltage supplied by the cmos battery is replaced by another source while the old battery is being disconnected and replaced.

Any ideas or tips on how this might best be done? I've got the soldering and electronic skills to do the surgery, but some pointers from anyone who's been down this path would be appreciated.

On to b):

Is this possible to do? Can the cmos password memory be reset or rewritten by a utility program running from DOS or Windows, for example? I assume there is no way to do this without resorting to low-level hardware access bypassing the user interface (otherwise it wouldn't be much of a security system).

Is there a factory default password worth trying that it might still be set to?

Any tips or pointers appreciated. Even if the cmos battery "bypass surgery" is successful, it only kicks the can down the road until the next battery wears out, and it would be nice to have a permanent solution.

[rkawakami]

Welcome to thinkpads.com!

Forum rules dictate that discussions of bypassing Thinkpad security systems is not allowed. However, I will answer some of your questions:

- There is no "default" password. Suggestions found on the internet to use IBM, PHOENIX, or other words will not work, useless of course whoever set the password used one of these words.
- There should be no way that a main battery swap would cause the invocation of a previously unset supervisor password, and then cause it to be "removed" when the battery is swapped again. Most likely what happened is that your mother pressed the F1 key during boot on that one occasion and got the password prompt. You can have her double-checked this by removing any main battery, use only the AC adapter, turn on the system and immediately press the F1 key. If the password prompt re-appears, her system has the supervisor password enabled.
- If the CMOS battery was dying (or died) enough to cause the BIOS real-time clock to lose its settings, that would have triggered a permanent supervisor prompt whenever the system is turned on; even without pressing the F1 key. The loss of time causes the BIOS to force the user to supply the correct date/time information. On a system that does not have the supervisor password set, the system boots into BIOS and allows the user to set the clock. If there is a supervisor password, the prompt is displayed and you are essentially locked out of the system until you can reset the time.
- It has been proven by me that a swap of a fresh CMOS battery IS possible without losing the BIOS time but that was only performed on an X61s system: http://forum.thinkpads.com/viewtopic.ph ... 63#p702263 I would suggest reading the entire thread so you know what's involved.

[plugger2]

Welcome to thinkpads.com!

Thanks!

Forum rules dictate that discussions of bypassing Thinkpad security systems is not allowed.

Bummer.

However, I will answer some of your questions:

- There is no "default" password. Suggestions found on the internet to use IBM, PHOENIX, or other words will not work, useless of course whoever set the password used one of these words.

Also bummer.

- There should be no way that a main battery swap would cause the invocation of a previously unset supervisor password, and then cause it to be "removed" when the battery is swapped again. Most likely what happened is that your mother pressed the F1 key during boot on that one occasion and got the password prompt.

Yes, well there is "should" and then there is "actually what happened".

It didn't happen just once, but everytime she tried to boot with the new battery installed.

Removing the new battery allowed the password check to be bypassed. Whatever condition was triggering it with the battery installed was not present when the battery was removed. But how long that lasts, I wouldn't like to guess. If it is the unexpected interaction of a charging battery in the circuit and a dying and marginal cmos battery, as the cmos battery degrades further, the problem could go from an intermittent to a hard error at any time.

I was hoping there was a window of opportunity to get some preventative maintenance done before that becomes the case.

You can have her double-checked this by removing any main battery, use only the AC adapter, turn on the system and immediately press the F1 key. If the password prompt re-appears, her system has the supervisor password enabled.

I'm sure it *does* have a supervisor password enabled, set by some previous owner. It's just never reared it's ugly head until now.

- If the CMOS battery was dying (or died) enough to cause the BIOS real-time clock to lose its settings, that would have triggered a permanent supervisor prompt whenever the system is turned on; even without pressing the F1 key. The loss of time causes the BIOS to force the user to supply the correct date/time information. On a system that does not have the supervisor password set, the system boots into BIOS and allows the user to set the clock. If there is a supervisor password, the prompt is displayed and you are essentially locked out of the system until you can reset the time.

Yes, I understand. That's exactly the "supervisor password lockout scenario" I was referring to.

- It has been proven by me that a swap of a fresh CMOS battery IS possible without losing the BIOS time but that was only performed on an X61s system: http://forum.thinkpads.com/viewtopic.ph ... 63#p702263 I would suggest reading the entire thread so you know what's involved.

Thanks for the pointer, I'll have a look...