Arch Linux

Vins

Member

From: Italy

Registered: 2005-12-14

Posts: 67

Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

Hi,

I have completed the setup of a dual boot configuration with Windows 8 + Arch Linux on a Samsung Book 7 (Series 7) NP740U3E (US version with HD4000 and touchscreen).

As the samsung-laptop module doesn't support UEFI anymore, I'd like to run Archlinux using the bios/legacy (CSM) mode. I can successfully start Arch in BIOS legacy mode from a USB key but there seems to be no way to do the same from the internal SSD (GPT partitioned).

I've tried in several different ways:

- Installing grub in BIOS mode, adding a Bios Partition on the SSD drive
- Installing Refind to see if it can detect legacy bootloader

Nothing works. I think it may be a BIOS issue. The SSD doesn't show up as a boot option (only the EFI bootloader or the external USB drive are listed).

I am thinking of downgrading the BIOS firmware (currently running on P05ABW but I can't find an older version).

Without the samsung-laptop module I can't manage the fan speed and the keyboard backlight.

Any ideas would be really appreciated.

Thanks!

Vins

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

I think you might have to turn UEFI off altogether (if possible).  The Thinkpad bioses allow you to  choose whether the MBR or the ESP is given priority when choosing to boot from the disk itself.

It might just be the case that UEFI is always given priority on your machine, but I have never owned a Samsung, so I don't really know.

Vins

Member

From: Italy

Registered: 2005-12-14

Posts: 67

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

If I disable UEFI completely (which in the Samsung BIOS is called 'CSM Only') I can only boot from an external USB device, as if the SSD is not even connected to the laptop.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

This machine has *only* that SSD you mention, doesn't it?  I wonder if your machine will allow you to boot off the sdcard slot.  Maybe you could put the /boot and MBR bootloader there and then just specify the root= on the other device.  Many times a bootloader is able to initalize more of the machine that some bioses will allow.  That is, it will boot a root filesystem on a disk that normally wouldn't be allowed by the machine itself.

Otherwise, I really have no good answers for you.  I'm not familiar with this machine at all.  I would probably just use UEFI and suffer the loss of the samsung-laptop module.

Edit: Did you try booting with UEFI to see if the samsung-laptop module is still not used with UEFI.  I seem to recall something on some mailing list about what the danger zone is for the capacity of the NVRAM, to which Samsung actually gave a response.  I never tracked progress from there, but if there is a known acceptable threshold, maybe this has been fixed…

BTW, it was the NVRAM being filled that would cause the Samsung machines to brick themselves.  This was a combination of bad garbage collection and the kernel being able to dump the panics to the NVRAM for later debugging (which is really a neat feature).  There was talk about a solution I remember, but you'll have to check to find out.

Boot the machine with a UEFI USB and run lsmod to see if the module is there.  The live media uses the standard repo kernel, so if it shows up there, it will also be usable from your installation.

Last edited by WonderWoofy (2013-08-26 03:44:58)

Vins

Member

From: Italy

Registered: 2005-12-14

Posts: 67

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

Thanks again for your reply!

I'll try to see if I can boot in bios mode using an external device (USB/device card) pointing to the root device on the SSD.

The samsung-laptop module has been disabled when running in efi mode, as reported in the latest commit: https://git.kernel.org/cgit/linux/kerne … &showmsg=1

Basically the workaround for preventing any issues with the Samsung UEFI firmware is .... not mess with the Samsung UEFI firmware :-)

Thanks!
Vins

gijom

Member

From: Belgium

Registered: 2014-04-04

Posts: 2

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

Hello Vins,

I encounter the same issue with the Samsung np900x3g (k01fr).
Did you find any good solution (if possible not involving external device)?

Thanks

gijom

Vins

Member

From: Italy

Registered: 2005-12-14

Posts: 67

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

Hello Vins,

I encounter the same issue with the Samsung np900x3g (k01fr).
Did you find any good solution (if possible not involving external device)?

Thanks

gijom

It has been a while but if I remember correctly  I had to format the whole ssd drive, switch to LEGACY/CSM mode, reinstall windows and then Arch.
Not sure if things are different with the latest bios versions.

V.

gijom

Member

From: Belgium

Registered: 2014-04-04

Posts: 2

Re: Samsung book 7 NP740U3E - Booting from SSD in BIOS (CSM) mode

Thank you very much! It works!