Removing Supervisor Password on a Lenovo T410s (In Vancouver)
A friendly person who took up one of my laptop contacted me that he has a Lenovo T410s. He could see the BIOS settings but could not change them, such as activating the fingerprint device . He asked if I could help to remove the lock.
We met on 2 May 2014 while I was on the way home. He showed me more details. When he started up the T410s and pressed F1 to go to the BIOS. A lock displayed asking for password. He pressed enter and could see the BIOS settings but they were all protected. As I know him and he could start up the Windows 7 Operating System inside, showing his ownership of the T410s, I accepted his request to remove the lock because I had tested removing password on a T40 before by swapping a EEPROM chip from a dead motherboard. However, it would be the last option that I would do because I did not have dead motherboard and the chip has online price of $35.
In internet, I found several more options. The easiest one is to remove the CMOS battery. I tested it. It did not work and have negative effect. When BIOS date and time were cleared, the T410s boot-up displayed date and time error and prompted for BIOS update. Since the BIOS was locked by password, the T410s could not get back to Windows Operating System.
Another option is to build a device to read the EEPROM chip and decrypt the password. It has too much work. In the meantime, the ower emailed me links to buy a EEPROM at $25 and a procedure from ex-employee of Lenovo to reset without any EEPROM chip for $17.
I searched further and found video on removing password by shorting the EEPROM pins. It has comments that it worked for T410s. Unlike removing CMOS battery, there is risk on frying the motherboard if wrong chip or pins are shorted. After confirming several source, I decided to test this option and did the following preparation and precaution:
- Removed the keyboard and inspect the motherboard. I found two tapes on the plastic sheet which cover the motherboard. I opened up the big square one which does not expose any chip. When I opened another one, I found a cut on the plastic sheet. I peeled it open and found a 8 pins chip.
- Verified the chip code on top with other source that it is a EEPROM chip.
- Took another plastic from a dead motherboard and cut a hole just big enough to expose the EEPROM chip. This is to avoid frying the motherboard when some other circuits were shorted accidentally. In one of my previous laptop fixing, I tried to locate motherboard problem when it had power, some sparkles came out if I shorted the wrong place.
- Taped a tweezer to fix the width of legs that would short the EEPROM pins 4, 5 and 6 exactly.
Without powering on the T410s, I attempted the shorting steps according to the video several times. It was to ensure that I did not short other pins.
When I was fully prepared, I powered on the T410s and ran the steps. The first time failed because I shorted the pins too early. The T410s did not go to BIOS. The second time failed too. I was too late that the T410s went into BIOS and displayed the lock. After trying several times, I got the BIOS screen displayed. It has password cleared and settings can be modified. The T410s can get back to Windows Operating System too.
I informed the owner. He was happy to get it back on 3 May 2014 morning. Thanks for his cakes and payment that I can use to buy parts for fixing further dead laptops.