On 23.04.2020 19:57, Marcin Owsiany wrote: > TL;DR: My laptop starts ~20x slower than normal. Booting Debian hangs > before the kernel starts. Windows 10 boots slow, but then works fine. > Hardware problem? > > More details: > > I bought a Lenovo IdeaPad Flex 5 in April 2019. It came with Windows > 10, I installed Debian buster on it (dual-boot with GRUB 2). Worked > flawlessly (with secure boot!) for ~8 months. > > In January 2020 after some reboot for the first time it started slow, > and hung while booting Debian. Windows boots slow too, but once it's > up it works just fine. BIOS SETUP UI is also very slow. > > Since it might not be obvious what I mean, here is a recording, with > detailed timeline in video description: > https://youtu.be/HCgO9UblqtI > > After a few reboots it came back to normal. Then this effect came and > went a few times, and now it's here for good. I cannot boot Debian at > all. I tried leaving it booting overnight once and it didn't show any > progress. Windows still works OK. Updating BIOS to the most recent > version did not help. > > I asked on the Polish Lenovo support forum > <https://forums.lenovo.com/t5/Laptopy-IdeaPad/Flex-5-drastyczne-spowolnienie-bootowania/m-p/5010338?page=1#5037024>, > the response was that "this model does not support dual boot (sic!), > they have had no similar reports in the past, and installing Linux on > it might have caused the problem". I'm shocked. > > Initially I thought this might have something to do with Windows > updates, because on the first occasion it seems to have disappeared > after Windows completed its scheduled update. But now I think it was > just a red herring. > > In my almost 30-year experience I have not encountered a problem which > does not go away after a cold reboot, but does go away after Windows > starts :-O > > My only theories now are: > - a hardware problem (but why does it go away once Windows boots?) > - a botched CPU microcode update (but I suppose there are checksums > which would prevent it from happening, so not likely). > > Any thoughts? > > Marcin I've watched your video and definitely I haven't seen anything like it before. I've seen slow BIOSes in the past, but not *that* slow. And it continues being slow even after it hits bootloader. I'd suspect either poorly tested Windows 10 update, which is known fact, Windows can update laptop BIOS without user's consent. Or some kind of malware/rootkit. These are rare, but still exist for BIOS and for UEFI. [1] It also could be a hardware problem where CPU\GPU runs on low frequency with failed attempts to rise it up. Or some device hogs some bus, generating interrupts in a loop, but never fails. The fact that after Windows starts it suddenly looks normal, could be because drivers take control over problematic device or Windows kernel applies some measures to circumvent known problem.
In the first case BIOS should be reflashed with image made exactly for your laptop model, downloaded from official Lenovo website. Reset BIOS settings to defaults after reflash and set them up again. In the second case I'd check PSU and battery and removed it, if it is detachable. Check if cooling fan is working. Then gradually strip all devices, like M.2\NVMe\SATA drives, mini-PCIe WiFi adapter, DVD drive, keyboard, touchpad, any connected USB devices, etc. Connect external USB keyboard if needed. If you will be disconnecting laptop LCD screen, make sure to disconnect PSU and battery first, to avoid possible permanent damage to ICs on motherboard. This should be enough to tell if this is something user serviceable. If device stripping helps, then by adding devices back one by one you will find the culprit. I'd be interested to know exact laptop model\part number, for personal statistics and possible further research. [1] https://www.welivesecurity.com/wp-content/uploads/2018/09/ESET-LoJax.pdf -- With kindest regards, Alexander. ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system ⢿⡄⠘⠷⠚⠋⠀ https://www.debian.org ⠈⠳⣄⠀⠀⠀⠀
