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 to do this have failed, and generally result in the error message "isolinux.bin missing or corrupt." when trying to boot. Is this possible to achieve with current version of isohybrid? Any help on how to achieve this is appreciated. Thanks Duncan
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 modification I'd need to look at to support this on a logical parttion? Would the change be in the isohybrid tool, or (I'm guessing more likely) in the actual MBR image that the tool writes over the ISO? On 28 December 2016 at 19:06, Duncan Elliot <dmelliot at gmail.com> wrote:> 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 to do this have failed, and generally result in the error > message "isolinux.bin missing or corrupt." when trying to boot. > > Is this possible to achieve with current version of isohybrid? > > Any help on how to achieve this is appreciated. > > Thanks > Duncan >
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 which isohd*.bin file is selected by which combination of options.> does anyone have suggestions for what modification I'd need to look at > to support this on a logical parttion?Sorry, not me. One will probably have to analyze the code of MBR and/or isolinux.bin to find out why it is not working with your situation. (Did you already tell which partitions exist and in which one do you want to put your ISO ?) Have a nice day :) Thomas
Le 28/12/2016 ? 09:06, Duncan Elliot via Syslinux a ?crit :> 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 to do this have failed, and generally result in the error > message "isolinux.bin missing or corrupt." when trying to boot. > > Is this possible to achieve with current version of isohybrid?Sorry if this is a silly question: why not use a GUID partition table instead of using logical partitions?> Any help on how to achieve this is appreciated. > > Thanks > Duncan