More actions
| EliteBook 850 G5 Not charging with broken USB-C port | |
|---|---|
| Device | EliteBook 850 G5 |
| Affects part(s) | USB C port |
| Needs equipment | CH341A, screwdriver, possible solder |
| Difficulty | ◉◉◌◌ Medium |
| Type | Teardown, Software |
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Problem description
- After disconnecting a USB-C charger, laptop reports power is still plugged in and charging indicator remains solid amber
- Any USB C peripherals are not recognized
Possible permanent fix (just theory for now)
This laptop was built around the same time as Thinkpad T480 and USB-C charging was new. The T480 had issues with the thunderbolt port due to the firmware constantly writing to a 1 MB eeprom chip. Eventually, the chip's storage would overfill and corrupt the firmware.
On the back of the 850's motherboard, there is a winbond 25q80 chip[1] that is 1 MB. Another user posted the dump of the chip that contained no null padding and seemed like the firmware was written twice and did not have enough room to write a third time.
Dump of Elitebook 850 G5 25q80 chip
Dump of overfilled T480 eeprom
Dump of correctly padded T480 eeprom
In theory it might be possible to create a padded version of the Elitebook's thunderbolt firmware and follow these steps.
Temporary Solutions
I bought a USB C to barrel jack connector very cheap on AliExpress which bypasses the faulty USB-C for charging.
Otherwise, doing a hard reset (press the power button for 10 seconds and the caps lock and num lock will flash) returns USB C functionality.