smbusb VS stm32-bootloader

On any BMS there will be a chip, sometimes 2, which are the brains of the operation. The TI bq-series are pretty common. Some of these have public documentation, some are private. A lot of them are password-protected if you want to overwrite the original programming. There are various tools for interacting with them, from free open source to paid You don't always need to reset it, sometimes just replacing the cells then shorting across the switching side of the output is enough. But without knowing what you're getting into it's a gamble.

Sorry, Vantage is Lenovo software, but it has a function to improve battery gauge accuracy. It made more sense when mentioned in the Thinkpad forum, but I figured I'd crosspost my request here too. That being said they of course did the major dick move of only ever adjusting measured capacity down, even if the cells were literally at 4.1V when the battery said it had run out. Therefore, I first used the smbusb utility to edit the dynamic battery data and blank out the battery full charge capacity (which actually sets it to the absolutely ridiculous 65535Wh). After that when running the gauge reset in Vantage the battery was more than happy to report a more realistic 102.78Wh of actual capacity, despite still reporting a design capacity of only 93.6Wh which thankfully didn't raise any issue. Unfortunately while trying to experiment with the BMS firmware further to try and adjust the voltage thresholds to better fit the new cells, I corrupted something. The BMS still reports and sort of works but whenever I try to make further edits to the firmware I am greeted with errors.

I've been playing around with my failing LGC 70++ 9-cell battery after re-celling it with SANYO 3500mAh cells. Had some great success with a tool called smbusb (got the battery to report as 105WH after a gauge reset in Vantage) but I think I killed the BMS eventually by flashing some wrong values and corrupting the firmware and can't seem to get it back. I've looked around eBay but most of the batteries on there are either for T410/T420 (yes I know you can make them work in T430, but they might use a different BMS chip) or ridiculously expensive for 10-year old batteries. So here I am hoping that someone here has an old, damaged, dead or unloved battery that I can take off their hands.

You can use SMBusb and something like an FX2LP. Then to connect it, I would just use some normal Dupont 0.1 connectors (make sure they have female -> male), or of course any piece of wire if you don't mind spending more time trying fiddling about.

See HERE for a device that lets you connect to the data pins on laptop packs and read info from them. Some packs you can find pinouts online, others you have to figure out yourself.

Here's a bootloader "library" that might be useful. You need to add your own code to get the actual firmware image from somewhere (UART, an SD card, or whatever), and then you just pass it off to the "library" for flashing.

Yes, unless you have something like an STM32 with a built-in bootloader. This can be used to update the regular bootloader. For example, this bootloader is capable of jumping to the built-in bootloader from software (as opposed to the "regular" method of pulling certain pins high or low at reset to cause the processor to run the built-in bootloader from ROM rather than the regular bootloader from flash).