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After setting UEFI to legacy boot mode, laptop did not boot at all, no POST either. Removing CMOS battery doesn't help either

Tags:
  • Laptops
  • Battery
  • Legacy
  • Boot
  • CMOS
Last response: in Laptop Tech Support
May 7, 2018 2:26:15 AM

Hi all,

so, I bought a second-hand laptop (thinkpad t440s) and wanted to check the hardware with memtest86+. For this though I needed to disable some UEFI settings to have the computer boot into legacy mode (following instructions here: https://askubuntu.com/questions/917961/can-i-boot-memte...)

After having disabled UEFI and enabled legacy boot, the laptop didn't boot anything at all, not even POST seemed to be enabled (upon pressing enter it beeped once though, but nothing further), just the LEDs were turned on and a blank screen was shown; no possibility to get into BIOS either.

So I thought, I'd reset BIOS by removing the connector of the CMOS battery. After having done so, the laptop still didn't boot anything at all, occasionally it beeped shortly twice though which indicates a parity circuit failure. Now, pressing the power button for a long time after shutting down and before starting up, or leaving the laptop without any CMOS battery nor main battery connected for half an hour didn't help either.

Somewhere I've read detaching and re-attaching RAM in order to investigate the two-beep circuit failure, but I can't imagine that this could be a cause behind my problem, since the computer booted nicely into windows 10 before, though I didn't test it thouroughly on a real-usage basis, so perhaps there might be a problem with the RAM, but I'd rather assume that it is related to my fiddling with BIOS and the CMOS battery.

Does anyone have any idea how I could proceed from here??

Any input is greatly appreciated, especially since this laptop is actually for a friend, and I'm feeling a bit embarassed about this issue....

More about : setting uefi legacy boot mode laptop boot post removing cmos battery

a b D Laptop
May 7, 2018 3:01:46 AM

One trick that sometimes helps is to unplug the laptop, remove it's battery, then disconnect the CMOS battery and hold down the main power button for roughly 30 seconds to drain any residual power in the system. It's at least worth trying.
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May 7, 2018 3:06:05 AM

Hi rocktalkrock,

unfortunately I've tried this already a few times. I can try again later though in the evening.
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Related resources
a b D Laptop
May 7, 2018 3:19:15 AM

Doeblinger said:
Hi rocktalkrock,

unfortunately I've tried this already a few times. I can try again later though in the evening.

A different trick, unplug the laptop, take out the main battery, then disconnect the CMOS battery. Wait a few minutes and then put the battery power-pack back into the laptop WITHOUT THE CMOS BATTERY.
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May 7, 2018 3:36:52 AM

Also something I already did. But perhaps I didn't press the button long enough after taking out the CMOS battery, or missed some other small step.

I will try all these combinations more thouroughly again in the evening and will update it here again.

Until then: so, you also seem to agree that this issue must be related to faulty BIOS settings which should be possible to be resetted by removing the CMOS battery, right? Can you think of any other possible cause?
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a b D Laptop
May 7, 2018 3:45:38 AM

No matter what changes are made in the BIOS, you should be able to clear the CMOS and re-enter BIOS. Try looking at the RAM again. If you have 2 sticks, try just 1. Make sure the RAM is inserted into the slot correctly.
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May 7, 2018 3:55:07 AM

I think so too! I was just getting a bit nervous since it's a newly bought laptop for a friend..

Alright, will try all these tricks again as well as inspecting the RAM, and gonna update once done with all of that.
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May 7, 2018 3:56:33 AM

You mentioned changing setting in bios, make you re-enable secure boot. Try that see if it boots
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May 7, 2018 4:14:48 AM

Hi th3p00r,

Unfortunately, I can't even get into BIOS at the moment since nothing boots at all, the laptop turns on but only shows a blank screen, not even POST-info is displayed.
Thus I can't revert the changes I've made..
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May 7, 2018 12:17:27 PM

So after coming home I tested it again, thouroughly. Since yesterday evening, so for almost 24 hours, the laptop was without power supply, main battery, and CMOS battery attached. Before plugging them in again, I kept the power button pressed for more than a minute, then put in the main battery (not the CMOS). Then the resulting beeps were what I think: 1 short 1 short 2 short, which would translate to a MB error (can only mean motherboard, right?) according to lenovo's site: https://support.lenovo.com/at/en/solutions/ht062270.

Then having it turned on again with the same setting resulted in: 1 short 1 short wich would translate to parity error.

Then having plugged in the CMOS battery again, resulted in: 1 short 1 short 2 short, which again hints at MB error.

I've tried many different variations of having main battery plugged in / out, CMOS in / out, power suppley on / off, but the very most of them result in 1 short 1 short. Sometimes nothing at all.

So all these signals seem to hint at problems with RAM then? But how can this be if all I did was just changing the boot mode? Before the laptop had booted fine, and right away after having changed that setting, it didn't work anymore at all. Is this some super-weird coincidence or can my BIOS - fiddling result in causing the RAM to either turn bad or starting to show that it has become bad?

Unfortunately since we just bought it, there is a warranty sticker attached to the lever of the RAM, so I can not change it without destroying the sticker and thus voiding the warranty, which I [watch your language] hope to not have done so already by changing something in BIOS and unscrewing the lid underneath, but then again there was no warranty sticker destroyed in this act.
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a c 540 D Laptop
May 7, 2018 12:23:57 PM

watch your language
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a b D Laptop
May 7, 2018 12:31:30 PM

Is the laptop still under warranty? I assumed it was not.
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May 7, 2018 12:37:51 PM

It was sold by a vendor with a one-month warranty.
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a b D Laptop
May 7, 2018 12:52:37 PM

Doeblinger said:
It was sold by a vendor with a one-month warranty.

So that warranty would be with the vendor (Amazon or Newegg), not Lenovo? That would be for return or repair?
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May 7, 2018 2:37:42 PM

It's a german vendor, and that would be for return. Wich I'm gonna inquire about tomorrow.
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