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Re: Unable to boot BIOS/GPT system.




On 11/22/18 8:24 PM, Daniel Fishman wrote:
> Hello,
> 
> I am trying to install Debian on a 4TB external HDD. Since I want
> to boot the HDD (also) on old systems which support only BIOS,
> and since the HDD is larger than 2TB, I decided to go with GPT
> partition table and BIOS boot (or, in other words: BIOS/GTP).
> I partitioned the HDD accordingly (see the details below), and
> installed Debian. During a pre-installation configuration the
> installer recognized BIOS boot partition, I configured the root
> partition as ext4 and installed grub into the disk's MBR. But
> when (after an installation) I am trying to boot the HDD, I receive
> an error message: 'error: unknown filesystem' and drop into a
> grub rescue mode.
> 
> What is the problem here and how it can be solved? It seems as
> though grub's Stage 1.5 loader (that is - core.img, which is
> supposed to be embedded in BIOS boot partition) doesn't contain
> modules needed to read ext4 filesystem, which seems very strange.
> 
> 
> Following are a bit more details about the partitions:
> 
> I used the following command to partition the HDD:
> 
> parted -s /dev/sdb mklabel gpt mkpart BIOS_boot ext2 1MiB 2MiB \
>   mkpart swap linux-swap 2MiB 16000MiB mkpart data ext2 16000MiB 100% \
>   set 1 bios_grub
> 
> [root@arch]# parted /dev/sdb unit MiB print
> Model: WD Elements 25A1 (scsi)
> Disk /dev/sdb: 3815415MiB
> Sector size (logical/physical): 512B/4096B
> Partition Table: gpt
> Disk Flags:
> 
> Number  Start     End         Size        File system     Name  Flags
>  1      1.00MiB   2.00MiB     1.00MiB                           bios_grub
>  2      2.00MiB   16000MiB    15998MiB    linux-swap(v1)
>  3      16000MiB  3815414MiB  3799414MiB
> 
> 
> Debian's installation was done on x64 BIOS-only system.
> 


Hi Daniel,

in case of BIOS and GPT you have to create a partition for second stage
of GRUB. If I can remember correctly its size should be less than 50MB.

HTH

Kind regards
Georgi