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The fifth model in Lenovo's L4xx series of 14-inch laptops. Released in 2014.

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How to remove SVP without knowing on L420?

I forgot the supervisor password for a lenovo thinkpad L420 on the BIOS. How do I reset it without tearing the laptop to pieces?

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@fivepointrekt you really cant. Try the ideas from here Ultimately you will have to perform some work as shown on here or contact Lenovo directly.

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Back before the Intel Boot Guard machines, you could find the ATMEL chip and short 2 lines out quickly (I don’t reveal these to avoid being caught up in a legal nightmare, but it’s been mentioned by others) or use a specific tool found online to clear this up. However, that hasn’t worked since the XX40 series :(. It only works on machines from the 390E to the XX30 series (with a few exceptions) since these are pre-Boot Guard.

These newer systems need to be reset with software only Lenovo has access to so you preserve the ability for the system to boot correctly - it exists, so it’s a matter of how willing they are to deny it’s something they can do. If you do it wrong on these, you’ll trigger the tamper checks done by the ATMEL chip and lock the machine out or get a checksum POST error - it really does depend but you’re in deep trouble either way and will have no way out besides a new motherboard. We can’t fix the tamper lockout, even on pre-Boot Guard systems. For these, you are going to need a motherboard or see if Lenovo will admit to being able to do a software reset at a discounted rate. You will also need a receipt to prove ownership.

The security chip tampering problem really didn’t matter much before since while it could be triggered, it wasn’t a common problem outside of the few corporate machines that actively set it to check. These newer machines either do not boot due to a failed hash check or lock the system out from booting at all.

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How do I check if it’s boot guard?


Is it at least a Haswell based system? Those are the systems that started to ship with Boot Gard. Haswell-present is Boot Guard while Arrandale-Ivy Bridge is not.

An easier way to ID it is the last 2 digits of the model. XX00-30 are not Boot Guard systems (too old) while XX40-present are.

Dell doesn't attempt to say it can't be done. The Dell laptops are a complete joke to crack if you know where to generate the master password. They even changed the generation scheme with Haswell and it has been cracked. I think they just don't care at this point.

Lenovo is the only company who has the ability to do it or can develop tools to get it done (that is known) who continues to actively deny a known fact. The Toughbook is probably genuinely impossible since those are sold to the military and consumers (special requirements), but there's nothing stopping Lenovo from making it resettable with a master password... They just don't say it can be done because they think security through obscurity works.


I finally got the courage to crack it open and pull out the cmos battery. There’s no password but it keeps saying to configure the bios by pressing f1. Can you help with the issue? Thanks.


I seriously hope it didn't have a POP. If it did you disabled the machine and all you have left is an unknown SVP.



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