Finally got that weird Lenovo boot loop to stop by pulling the CMOS battery for a full 10 minutes instead of just 30 seconds.

I mean, I'd tried the usual quick reset a bunch of times, but leaving it out that long while the main battery was disconnected too actually cleared whatever was stuck in the UEFI, maybe it's just me but has anyone else had to do that for the newer ThinkPad models?

3 comments

3 Comments

carter.thea1mo ago

jesse just mentioned maybe it was a loose connection, but here's something nobody's said yet - the orientation of the CMOS battery when you put it back in matters more than you'd think. I've noticed on some of the newer models, there's a tiny bit of play in the connector that can make it not sit flush unless you really push it down on a specific angle. So maybe you fixed it just by reseating it properly during the long wait, not the wait itself. And christopher's right about the capacitors, but I'd add that even after pulling the battery, pressing the power button for 30 seconds with everything disconnected helps drain those caps faster. Just something to try next time instead of waiting a full ten minutes.

christopher_ross3mo ago

Yeah, the 30 second thing is basically useless on modern boards. The capacitors hold a charge way longer than people realize. I had the same exact problem with a T14 last month, nothing worked until I left the CMOS out for like eight minutes with no power cable attached. It's like the UEFI needs that full power drain to truly reset.

jesse_west3mo ago

Hold on, why are we blaming the quick reset? Maybe you just got lucky with the ten minute wait. Could be a loose connection you fixed when you put the battery back in. I've done the 30 second pull on my own newer laptop and it worked fine, so maybe the problem was something else entirely. Doesn't it seem like we're just guessing without any real proof?