First post, by User5518
- Rank
- Newbie
The Dell Latitude X1 is a compact subnotebook from 2005.
Around 2007, I bought it for the first time and sold it around 2012. I repurchased it in 2014 and sold it again around 2020. Now, in 2025, I’ve bought it once more, and this time, I plan to keep it.
The device runs perfectly. I’ve upgraded it with an SSD (using a 50-pin PATA -> ZIF -> mSATA adapter), added 2GB of RAM, replaced the b/g-Wi-Fi card with an n-standard card, and installed a new CR2032 battery. This means the little Latitude is fully maxed out:
I’ve set it up with dual-boot Windows XP and Debian 12, though I currently use Debian more often.
However, the X1 has one significant issue: the battery.
The remaining capacity: 5.1% of 2400mAh. 🙁
I thought, “Okay, I’ll just replace the battery cells and bring it back to life.” So, I opened up the battery.
I charged the new cells to roughly the same level (around 4.0–3.9V) and balanced them using a 4.7-ohm resistor until all cells reached 3.95V. After assembling the battery and inserting it back into the laptop, I booted it up. The result? The battery was recognized – but still with 5.1% remaining capacity. It wouldn’t charge, showing the status: “Waiting to charge.”
I then inspected the Battery Management System (BMS) and found this IC:
This is an EEPROM chip, which I attempted to read using my CH341A Mini Programmer. However, using the supplied clip, I couldn’t read the EEPROM – tools like "flashrom" didn’t detect the IC.
Next, I soldered wires to the pins (SDA, SCL, VCC, GND, and WP) and connected them to the programmer. Same result: the IC wasn’t detected:
So, I desoldered the S24C01B from the BMS and mounted it onto a small adapter board:
This finally allowed me to read the IC:
This is the dump, I downloaded from the EEPROM:
E9007A00 B4000000 88443700 0000E2FF 00A58B32 2A03FFFF FFFF8432 0D045400 FFFFFFFF FFFFFFFF FFFF0A44 454C4C20 54363133 37202020 20202020 FFFF0000 48074607 4407FFFF FFFFEC0B EA0BE80B FFFFFFFF 002A8D01 00F30FFF 014521FF 43CC11FF F2BB21FF A55B39FF 520538FF FFFFFFFF DE00FFFF 7017FFFF 64990101
Now, I’m stuck. In theory, I’d need to edit the dump to reset the battery’s capacity and allow it to charge again.
But without a datasheet for Dell’s BMS, this might be impossible. Does anyone here have experience with this or know how to proceed?
