SOLVED

Thank you all. The issue was mechanical in nature, but it wasn't the battery, but either the board or the SIM that went odd.

After backtracking the issue a lot, I noticed it started happening virtually the same day I got my new car (thank you, it's a beawt-she is). Main difference being, the old one was a high range executive, and the new one is way more sportier. The chairs are very different, and, when I was sitting and driving I probably pressed the phone and (or) bent it a little. As a result, the CMT signal was logged and from that point on, regardless of length or restoring the shape of the phone.

Once triggered, the GSM modem would keep resetting from once every 5 minutes to 4-5 a minute until giving up and crashing.

I have moved the phone to the other pocket and this is my second consecutive day (6th consecutive trip) with no issues, no reboots, no shutdowns and syslog is clean as a whistle.

I live on the first floor, so my wifi extends aaaaalllmost to my car. Also, at work, we have several wifis, all of which end in the parking lot (after Police looked us up for tracking people who sat in cars at night doing illegal stuff on our wifi). In both cases, sitting in the car triggered the bug within seconds of wifi end-of-range.`

Thanks again to everyone I have dragged in this silly quest of mine to debug a hardware problem through software. And I would (and have) dug deep to find a software error code for "you bent the board".

In addition to moving the phone, I also did the following (for posterity)

* Spread apart the battery connectors, tighten the on-battery connectors (No effect, it was already firm)

* Cleaned the SIM with a specialized isopropyl (sp?) alcohol, along with the contacts on the phone side.

* Raised the on-phone contacts for the SIM a little. I now feels like the springs keep the SIM pinned to the back of the clamp

* Tighten the two springs that hold the battery in place. Seemed firm, but couldn't hurt. Except my fingers when I pull the battery out. Oh well.

Other than the first, all of these were done before the first successful trip, so I don't know which helped. Battery seemed non corroded, non loose and clean. I doubt it's that.

However, after handling for years, the SIM was most likely greasy and dusty (even if invisible) and the contacts that are used to connect SIM to phone were quite weak. My money is on that one. And the pressure.

I'll drive again tomorrow with it in my old pocket. If it survives, the SIM/holder was loose.