search for: partok

Hi, H. Peter Anvin: > It means that the .iso can be booted from a partition using any of the > standard MBRs (not necessarily altmbr), But the --partok MBRs (isohdpp*) stem from altmbr ? If so: don't they need the partition number patched in ? (If not: i have to rethink the link to article "Mbr" at http://www.syslinux.org/wiki/index.php/Isohybrid#MBR_selection ) > One of the main uses is for backup partitions -- often distro...

Hi, i am trying to document the MBR selection by isohybrid option --partok. I assume it is related to "altmbr.bin" as described in http://www.syslinux.org/wiki/index.php/Mbr But there i read "altmbr.bin [...] boots from a partition with fixed number, see below." The "see below" probably refers to "The altmbr.bin (all 3 variants) is onl...

On 06/25/2014 01:16 AM, Thomas Schmitt wrote: > Hi, > > i am trying to document the MBR selection by isohybrid option --partok. > > I assume it is related to "altmbr.bin" as described in > http://www.syslinux.org/wiki/index.php/Mbr > But there i read > "altmbr.bin [...] boots from a partition with fixed number, see below." > > The "see below" probably refers to > &quo...

Hi, I have been attempting to set up a multi-boot USB stick (i.e. multiple bootable ISO images on the one stick) I have had good success by: - processing ISO with isohybrid (with "partok" flag) - dd'ing ISO to primary partitions on the USB stick (e.g /dev/sdc2, /dev/sdc3, /dev/sdc4) - installing grub to USB stick and configuring to chainload to these partitions To remove the limit of 4 partitions, I would like to do the above but utilise logical partitions. All my tests t...

Op 2014-06-20 om 15:56 schreef Ady: > > The Perl variant, isohybrid.in, seems to be getting left behind > regarding several patches. I don't recall whether there is at least > some mention in the isohybrid docs about the existence of 2 variants > included in Syslinux (and that is in addition to other isohybrid > methods outside Syslinux). Is there any reference? >

Hi, On 23/06/2014 12:07, Thomas Schmitt wrote:> Hi, > > i have written an introduction to isohybrid and put it on > the discussion page of the ISOLINUX wiki. > > http://www.syslinux.org/wiki/index.php/Talk:ISOLINUX#Proposal_for_description_of_isohybrid > > Review and proposals are appreciated. Caveat emptor: this is a review by an end user (not a developer), who

Hi, Duncan Elliot wrote: > As far as I can see, this essentially trims off the first 3 bytes of the > custom isohybrid MBR image before applying it to the ISO. You probably mean this line: memcpy(mbr, &isohdpfx[hd0 + 3 * partok], MBRSIZE); The indize do not apply to bytes but to byte arrays of size MBRSIZE. extern unsigned char isohdpfx[][MBRSIZE]; (hd0 + 3 * partok) selects a particular MBR template from an array of six MBRs. See also http://www.syslinux.org/wiki/index.php?title=Isohybrid#MBR_selection It tells...

Hi, following will be 6 patch proposals for isohybrid.c 1: Encode GPT partition names as UTF-16LE 2: Correct blocking factor in APM partition block counts 3: Correct end block address of first GPT partition 4: Write GPT backup to the very end of the image 5: Change all fseek(3) to fseeko(3) 6: Introduce option --mbr and make isohybrid.c compilable standalone If the form needs adjustments,

Thomas Schmitt wrote: > Since we know that the isolinux.bin binary is well ok on other partitions, > i'd say that the MBR code does not load the right blocks from disk when > it wants to get isolinux.bin. Yes, these are my thoughts as well. I think the jump from GRUB to the isohybrid code on the logical partition is working fine, but when the isohybrid code is trying to jump to

I've attempted to understand what the isohybrid tool is doing, specifically with the "--partok" flag. As far as I can see, this essentially trims off the first 3 bytes of the custom isohybrid MBR image before applying it to the ISO. Can anyone explain how this enables the ISO to "be happy" on a partition, rather than whole disk? And does anyone have suggestions for what modi...

...mx.net> wrote: > Hi, > > Duncan Elliot wrote: >> As far as I can see, this essentially trims off the first 3 bytes of the >> custom isohybrid MBR image before applying it to the ISO. > > You probably mean this line: > > memcpy(mbr, &isohdpfx[hd0 + 3 * partok], MBRSIZE); > > The indize do not apply to bytes but to byte arrays of size MBRSIZE. > > extern unsigned char isohdpfx[][MBRSIZE]; > > (hd0 + 3 * partok) selects a particular MBR template from an array of > six MBRs. See also > http://www.syslinux.org/wiki/index.php?ti...

Hi, Duncan Elliot wrote: > What is the thought process of clearing the ISO MBR? It is not necessary in the partok case, because the partition to which you copy the image encloses the ISO, exposes it for mounting, and protects it from partition editors. (Another idea from assembler riddling turned out to be a red herring.) Without understanding the language or the BIOS habits of MBR booting, i assume that th...

...g something on its initrd to be able to coexist with other linux distros on the same USB drive, - After that, I build a new remastered iso9660 file with mkisofs or xorriso, - If I use xorriso, I select isohdppx.bin as the MBR file. If I use mkisofs I need to postprocess the image with isohybrid --partok. The menu entry on syslinux.cfg for each partition is as simple as: Konsole output LABEL ZeroShell MENU LABEL ^ZeroShell COM32 boot/syslinux/c32/chain.c32 APPEND guid:xxxxx 5 So, I'm chainloading the boot sector of an hybrid iso image dumped to a partition. Everything works as expected wit...

...usually 63 for Windows XP or older." So if GRUB hands the partition table entry of /dev/sdc5 over to the isohybrid MBR, then the isohybrid MBR code will see a ridiculously low start address of the partition and thus load the wrong blocks from disk instead of the content of isolinux.bin. The partok isohybrid MBR would have to look up the extended partition in the disk MBR and then hop along the chain of EBRs until it finds itself by some magic number. Currently this looks quite hopeless for 432 bytes of code. One could throw out the noop commands which reserve space for the fake Apple Partit...

...> mentions sgdisk with the important warning that you need a few unclaimed > blocks at the end of the disk device. > "GPT stores a secondary table at the end of disk. [...]" > > Before starting this endeavor, one should test by some USB stick whether > the isohybrid --partok MBR is working in GPT partitions. (Code is present > but how much was it tested ?) > Also you'd have to test whether all operating systems on the disk are > able to mount what they need from GPT. > > > Have a nice day :) > > Thomas >

Hi, Ady wrote: > We seem to be suggesting to just dd' the first 432 bytes of their USB > devices with Martin's isohybrid Yes. As long as it is not about the old Macs which the APM of Fedora and some Gentoo ISOs wants to make boot, and not about ISOs made with isohybrid options --partok -ctrlhd0 --forcehd0. > which would be the step-by-step instructions for users of other > isohybrid images? Copy at most 432 bytes to the start of USB stick or ISO image file: iso=/dev/sdc or iso=image.iso dd conv=notrunc if=isohdpfx.bin.170324 bs=1 count=432 of="$iso"...

...get to the same undecidable discussions about cylinder size which we had a while ago. We did not really make progress with getting this well documented. -e , -t, -i are MBR specific. -o is a bit questionable, as a non-zero value will normally make the partition unmountable. --forcehd0, --ctrlhd0, --partok choose the built-in MBR template. They all need exploration and lots of background information. > _ basic examples; I claim that isohybrid output.iso isohybrid --uefi output.iso are basic. > _ resources, see also, more info... I take proposals. > http://www.syslinux.org/wi...

...printf(FMT, " --forcehd0", "Assume we are loaded as disk ID 0"); @@ -122,6 +269,8 @@ check_option(int argc, char *argv[]) { "forcehd0", no_argument, NULL, 'f' }, { "ctrlhd0", no_argument, NULL, 'c' }, { "partok", no_argument, NULL, 'p'}, + { "uefi", no_argument, NULL, 'u'}, + { "mac", no_argument, NULL, 'm'}, { "help", no_argument, NULL, '?' }, { "verbose", no_argument, NULL, 'v' }, @@ -183,6 +332,14 @...

...scussions about > cylinder size which we had a while ago. We did not really make > progress with getting this well documented. > -e , -t, -i are MBR specific. > -o is a bit questionable, as a non-zero value will normally make > the partition unmountable. > --forcehd0, --ctrlhd0, --partok choose the built-in MBR template. > > They all need exploration and lots of background information. > > > > _ basic examples; > > I claim that > > isohybrid output.iso > > isohybrid --uefi output.iso > > are basic. > > > > _ resourc...

...; Sorry if this is a silly question: why not use a GUID partition > > table instead of using logical partitions? Duncan Elliot wrote: > Not a silly question, I had the same idea and had tried it out but it > didn't work (same error msg). This would be a SYSLINUX bug. After all the partok isohybrid MBR does have code for reading the start LBA from a GPT entry. I am wondering about the meaning or reason of "+20" in this assembler line: movl (32+20)(%si), %ecx Why that extra offset 20 on the byte offset 32 which is specified by GPT specs (UEFI 2.4, 5.3.3) ? (Do i get...