Re: [gentoo-user] Re: Change EFI to BIOS Boot
2014-04-19 12:34 GMT-03:00 Tom H : > On Sun, Apr 13, 2014 at 11:08 AM, Jonathan Callen wrote: >> On 04/12/2014 08:19 AM, Tom H wrote: >>> >>> You can have a gpt partition table with BIOS but if you want to boot from >>> that disk, you need a >>> bios_boot partition (which the OP has) for grub to embed a binary. >> >> Technically, I don't think you need a bios_boot partition if you leave >> enough space between the >> partition table and the first partition (I don't recall having a problem >> when my first partition >> started 2048 sectors (1MiB) into the disk). > > You're correct if you're talking about an msdos-labelled disk with > bios firmware because having the first partition start on 2048 as it > does now rather on 63 as it used to because the post-mbr gap will > always be big enough for grub to embed core.img. > > But on a gpt-labelled disk with bios firmware, there's a > mbr into which grub embeds boot.img but there's no post-mbr gap. So a > bios_boot partition's needed in order to embed core.img (IIRC parted > calls it grub_bios or bios_grub). > As I could not fix it, I solved it making backup, formating with ms_dos table, and restoring backup. :P
Re: [gentoo-user] Re: Change EFI to BIOS Boot
On Sun, Apr 13, 2014 at 11:08 AM, Jonathan Callen wrote: > On 04/12/2014 08:19 AM, Tom H wrote: >> >> You can have a gpt partition table with BIOS but if you want to boot from >> that disk, you need a >> bios_boot partition (which the OP has) for grub to embed a binary. > > Technically, I don't think you need a bios_boot partition if you leave enough > space between the > partition table and the first partition (I don't recall having a problem when > my first partition > started 2048 sectors (1MiB) into the disk). You're correct if you're talking about an msdos-labelled disk with bios firmware because having the first partition start on 2048 as it does now rather on 63 as it used to because the post-mbr gap will always be big enough for grub to embed core.img. But on a gpt-labelled disk with bios firmware, there's a mbr into which grub embeds boot.img but there's no post-mbr gap. So a bios_boot partition's needed in order to embed core.img (IIRC parted calls it grub_bios or bios_grub).
Re: [gentoo-user] Re: Change EFI to BIOS Boot
On Sun, 13 Apr 2014 19:21:56 -0300, Facu Curti wrote: > > > When I installed gentoo, I do that with UEFI, and gpt partitions. > > > But right now, I tried to install XEN, and this not works with EFI. > > > I cant wait until somebody fix this problem, So i'm thinking to > > > change "EFI" to "BIOS" boot. > I could not fix it, so I'm going to format the computer. I will make a > backup from system,format as ms_dos, and then restore backup. The partition table format is not the same as the bootloader. It is quite possible to use GPT partition tables with BIOS firmware, as long as you have that 1MB partition of type EF02 at the start of the table. -- Neil Bothwick Never wrestle with a pig. You both get dirty but only the pig enjoys it. signature.asc Description: PGP signature
Re: [gentoo-user] Re: Change EFI to BIOS Boot
On Sat, Apr 12, 2014 at 06:06:13PM -0700, walt wrote: > On 04/12/2014 03:45 AM, Facu Curti wrote: > > Hi all. First at all i apologize if my english is not enough. > > When I installed gentoo, I do that with UEFI, and gpt partitions. But > > right now, I tried to install XEN, and this not works with EFI. I cant > > wait until somebody fix this problem, So i'm thinking to change "EFI" to > > "BIOS" boot. > > > > So, I deleted the efi (/boot/efi) partition, edited make.conf, and deleted > > /etc/default/grub. > > > > After that, I made a new partition with bios_grub > > flag. As explained in [1]. And reinstalled grub2 (with new flags). > > But I can't boot. > > What happens when you try to boot? Can you see the grub2 menu screen? > No, I cant see grub menu. It just restarts. I could not fix it, so I'm going to format the computer. I will make a backup from system,format as ms_dos, and then restore backup. If anyone can give me any sugestion, I will appreciate that. Thank you all for help. Bytes! ;)
[gentoo-user] Re: Change EFI to BIOS Boot
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 On 04/12/2014 08:19 AM, Tom H wrote: > On Sat, Apr 12, 2014 at 7:23 AM, Volker Armin Hemmann > wrote: >> Am 12.04.2014 12:45, schrieb Facu Curti: >>> >>> Partition Table: gpt >> >> : This > > You can have a gpt partition table with BIOS but if you want to boot from > that disk, you need a > bios_boot partition (which the OP has) for grub to embed a binary. > > Technically, I don't think you need a bios_boot partition if you leave enough space between the partition table and the first partition (I don't recall having a problem when my first partition started 2048 sectors (1MiB) into the disk). - -- Jonathan Callen -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.22 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCgAGBQJTSqhYAAoJELHSF2kinlg4tnEQAJWEWwHhylqn3yrPfdtung3Z 3Ugifz04glSpBmaIGWBOO8DaTs/9Tz37lgPtpBeklDvehEdtqPH3RsTqpA/o5Eme 87kyFIY1w095TONvYd+N4W47wkx9oZ6FJ0TBnZUd3c+K4E0kJgC/p3W8xo9f6B7l Isl2EbCLW/AiYHj47I/qV+MDmAhdrJpx+T5FEnalSknPfJmvd0HPbxKbBOD49Doc 2VO8+K2ouGBpZ9la+kx7YeHSY4XoaAbsb3XEg0U96cnIdvXI8Pa8gF2vYg46AHtW BklKzCEVMnDWupGgfbs+06ysq6ubCmP/gsjuLZop90hhYFctWNr4yRqsxqzjD+fl 2v/jRqy5GIwdIbwKo/HCuPFWQ+D/l1jaQ0Id78TO0nKgXPeYXuW7alz1HBD7RhIL 4cF3ColFquDm3dRCi13qgrBSyfYD8jUVrkMJtBVSzD3HlKftQeEgnb8ClSdFP+t8 re7m/K8LuqyowlNm1s0gQlx+hGcHR1C2ERDCleyVdygNM+pXVTUdPBnhFE2w6L3g urP77q1MQ3XPkzUnusWU8UQPw3gZ2DqeMMVlNohj1Fhqm8WWBIkf5j49YzTCk5XT GVvMZbsxyg+a00wwwFmmd2287PvOBEKef5hXx5xIJsAp7T2+rGQCiF28Z2/jWTEG eUPkDLjJldc/b0dnlSdF =/6My -END PGP SIGNATURE-
[gentoo-user] Re: Change EFI to BIOS Boot
On 04/12/2014 03:45 AM, Facu Curti wrote: > Hi all. First at all i apologize if my english is not enough. > When I installed gentoo, I do that with UEFI, and gpt partitions. But > right now, I tried to install XEN, and this not works with EFI. I cant > wait until somebody fix this problem, So i'm thinking to change "EFI" to > "BIOS" boot. > > So, I deleted the efi (/boot/efi) partition, edited make.conf, and deleted > /etc/default/grub. > > After that, I made a new partition with bios_grub > flag. As explained in [1]. And reinstalled grub2 (with new flags). > But I can't boot. What happens when you try to boot? Can you see the grub2 menu screen? If you can see the grub2 menu screen you should try using the grub2 command shell (type "c" to enter the command shell) which will allow you to experiment with all of the grub commands that you compiled into the grub2 package. If you can get to the grub shell prompt you can hit TAB to see a list of available grub commands. The important point is this: any grub command that works from the grub shell prompt can be typed *verbatim* into a grub2 'menuitem' stanza. The first time I used grub2-mkconfig I noticed that it generates config files that strike me as a bit hysterical (excuse the sexist adjective).
