I have a computer that had a 32 bit os on it when I got it, I thought it was 32 bit. So installed debian-7 32 bit. I latter upgraded the kernel to pae, and then to 64bit. It is now a 64bit kernel, and 32bit user-land.

I am trying to upgrade to debian-8 64bit, by doing a fresh install. However when I tell computer firmware/bios to boot from the CD, it is not recognising operating-system on CD. It says no operating system found. Is it possible that the bios is programmed to not allow a 64bit boot? If so how can I install the OS?

computer : Acer aspire 5228


Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                2
On-line CPU(s) list:   0,1
Thread(s) per core:    1
Core(s) per socket:    2
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 23
Stepping:              10
CPU MHz:               1795.640
BogoMIPS:              3590.97
L1d cache:             32K
L1i cache:             32K
L2 cache:              1024K
NUMA node0 CPU(s):     0,1

cat /proc/cpuinfo

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Celeron(R) Dual-Core CPU       T3000  @ 1.80GHz
stepping        : 10
microcode       : 0xa0b
cpu MHz         : 1795.640
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 1
cpu cores       : 2
apicid          : 1
initial apicid  : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm xsave lahf_lm dtherm
bogomips        : 3590.97
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

Operating system info:

uname -a

Linux richard-laptop 3.2.0-4-amd64 #1 SMP Debian 3.2.81-1 x86_64 GNU/Linux

cat /etc/debian_version


aptitude show grub-pc

Package: grub-pc
State: installed
Automatically installed: no
Multi-Arch: foreign
Version: 1.99-27+deb7u3
Priority: optional
Section: admin
Maintainer: GRUB Maintainers <pkg-grub-devel@lists.alioth.debian.org>
Architecture: i386
Uncompressed Size: 488 k
Depends: debconf (>= 0.5) | debconf-2.0, grub-common, grub2-common (= 1.99-27+deb7u3), grub-pc-bin (=
         1.99-27+deb7u3), ucf
Conflicts: grub (< 0.97-54), grub-coreboot, grub-efi-amd64, grub-efi-ia32, grub-ieee1275, grub-legacy
Replaces: grub, grub-common (<= 1.97~beta2-1), grub-coreboot, grub-efi-amd64, grub-efi-ia32, grub-ieee1275,
          grub-legacy, grub2 (< 1.99-27+deb7u3)
Description: GRand Unified Bootloader, version 2 (PC/BIOS version)
 GRUB is a portable, powerful bootloader.  This version of GRUB is based on a cleaner design than its
 predecessors, and provides the following new features:

 * Scripting in grub.cfg using BASH-like syntax.
 * Support for modern partition maps such as GPT.
 * Modular generation of grub.cfg via update-grub.  Packages providing GRUB add-ons can plug in their own
   script rules and trigger updates by invoking update-grub2.
 * VESA-based graphical mode with background image support and complete 24-bit color set.
 * Support for extended charsets.  Users can write UTF-8 text to their menu entries.

 This package contains a version of GRUB that has been built for use with traditional PC/BIOS architecture.
Homepage: http://www.gnu.org/software/grub/

CD info: it was obtained on the cover of a magazine and was used to install my other laptop. (I added some newlines to the below, to make this output more readable):

file -Lsk /dev/cdrom
/dev/cdrom: sticky # ISO 9660 CD-ROM filesystem data 'LXFDVD199                       '
(bootable)\012- x86 boot sector; GRand Unified Bootloader, 
stage1 version 0x79, boot drive 0xbb, 
stage2 address 0x8e70, 1st sector stage2 0xb8db31c3, stage2 segment 0x201; 
partition 1: ID=0xee, starthead 0, startsector 1, 9003999 sectors, extended partition table (last)\011, code offset 0x52
  • How did you make the install CD? – Tero Kilkanen Jul 24 '16 at 9:54
  • @TeroKilkanen Added info on CD to question (it has been used before, it come with a magazine). – ctrl-alt-delor Jul 24 '16 at 10:17

From the above lscpu command output you can see that architecture currently in use is x86_64 and CPU is capable of operating in both 32bit and 64bit modes. So your boot loader is allowed to boot from a 64bit image.

I recommend you use the latest official image of Debian by obtaining it from here, you can download its torrent file in which case you need a BitTorrent client to download Debian CD/DVD images. Here's the link for amd64 CD and this one for amd64 DVD.

You can also get it from their official HTTP/FTP Server from this page.

For installation instruction this article would be really helpful.

  • I added some operating system detail, I note that the firmware's boot loader is not booting into 64 bit mode, as grub is 32 bit. I do not know if grub boot loader differs for different kernels, or how a 32bit grub boot-loader can start a 64bit kernel. – ctrl-alt-delor Jul 24 '16 at 11:59
  • I guess you need to completely wipe everything on your system and then make a fresh Install of Debian 8 on your laptop, maybe that way the firmware of your boot loader changes into 64bit and then it'll be able to start a 64bit Kernel (e.g. Debian 8.5 64bit). This link contains instructions on how to fresh install Debian 8 on your system. – Parsa Samet Jul 24 '16 at 13:15
  • That is what I am doing. It is the computers firmware that is not booting the CD, not OS or grub. I have clarified question. – ctrl-alt-delor Jul 24 '16 at 13:19
  • As far as I know, you can't do anything unless you can update your firmware so that it adds support for 64bit based architectures. anyway I suggest you ask for help from their official mailing list by subscribing and then send your question to debian-user@lists.debian.org – Parsa Samet Jul 24 '16 at 13:31
  • So is the answer “Yes: A computer needs firmware support to boot 64bit.”? – ctrl-alt-delor Jul 24 '16 at 15:07

I did not get it to a full 64bit OS, but it is now running Debian jessie 32bit, with 64bit kernel, and 64bit virtual-box. (virtual-box has to match the kernel).

From this it looks like I could upgrade most of the system to 64-bit. However I assume that if I upgrade grub, then the firmware boot loader will refuse to load it.

Therefore it should be possible (if I am correct), to have a near 100% 64-bit system, but a 32-bit grub.

Note: This does not seem correct, as I thought that a 32bit boot-loader, can not load a 64bit operating system. Or a 32bit operating system load a 64bit process.


I eventually got it to work for debian 9, using a multiarch installer. I do not know if it is possible for older versions of debian.

See answer here Installing debian amd64 on laptop that refuses to boot 64bit system

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