search for: isolinux_hybrid_signature

David Christensen wrote: > It looks like the call to "error" (line 276) is made if a summation of > the bytes in the first four sectors of a partition don't add up to > HYBRID_MAGIC (?). HYBRID_MAGIC = 0x7078c0fb isolinux_hybrid_signature = 0x7c00+64 ... cmpl $HYBRID_MAGIC,(isolinux_hybrid_signature) jne bad_signature ... bad_signature: call error .ascii "isolinux.bin missing or corrupt.\r\n" No. It looks for the value HYBRID_MAGIC at position isolinux_hybrid_signature in memory. -- MartinS

Hi, > The ISO will boot successfully (when chainloaded from grub) on 2 and > 3, but not on 5 and 6. Did you try with a boot loader other than GRUB ? Afaik, the MBRs of newly bought USB sticks often contain code which hops on the MBR code of the partition that is marked by the boot flag. At least one could exclude that your problem is in a GRUB peculiarity. Have a nice day :) Thomas

...ON_SUPPORT defined. One can see the error message text in there: bad_signature: call error .ascii "isolinux.bin missing or corrupt.\r\n" It seems to be reached only if the seen isolinux.bin does not bear the magic number of isohybrid capable isolinux.bin. cmpl $HYBRID_MAGIC,(isolinux_hybrid_signature) jne bad_signature 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. What happens if you use a partition editor to delete all MBR partitions from the ISO ima...

Thomas Schmitt wrote: > I ponder whether it would be possible to create a diagnostic MBR > which does not necessarily have to boot but rather tells what the > isohybrid MBR would perceive: Presence of partition table, > EBIOS or CBIOS, block address used with INT 13, content of the block > read by the first INT 13, ... ... > The diagnostic MBR should only use 432 bytes because at

...used on an ISO image in hybrid mode. * * This doesn't follow the El Torito spec at all -- it is just a stub * loader of a hard-coded offset, but that's good enough to load * ISOLINUX. */ #define DEBUG_PRINT 1 #include "adjust.h" .code16 .text HYBRID_MAGIC = 0x7078c0fb isolinux_hybrid_signature = 0x7c00+64 isolinux_start_hybrid = 0x7c00+64+4 .globl bootsec /* Important: the top 6 words on the stack are passed to isolinux.bin */ stack = 0x7c00 partoffset = (stack-8) driveno = (stack-14) heads = (stack-16) sectors = (stack-18) ebios_flag = (stack-20) secpercyl = (stack-24) BIOS_kbdf...

Thomas Schmitt wrote: > I have some problems understanding the details of the program's flow. > > - The code inside PARTITION_SUPPORT is supposed to be inactive with > MBR isohdpfx.bin. It belongs to isohybrid --partok which is equivalent > to MBRs isohdppx*.bin. Debian uses isohdpfx.bin. Yes. isohdpfx.bin is generated from isohdpfx.S in which PARTITION_SUPPORT is not

...e: > > bad_signature: > call error > .ascii "isolinux.bin missing or corrupt.\r\n" > > It seems to be reached only if the seen isolinux.bin does not bear the > magic number of isohybrid capable isolinux.bin. > > cmpl $HYBRID_MAGIC,(isolinux_hybrid_signature) > jne bad_signature > > 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. > > > What happens if you use a partition editor to d...

Hi, C/H/S addressing and reading of first block seems to be ok in isohdpfd.bin. The main suspect for the failure of the attempt with isohdpfd.bin is the number or content of the blocks read after the first one. But i have no clue why isohdpfc.bin should do better than isohdpfd.bin. They differ just by one instruction (JC = 0x72 versus JMP = 0xEB) which both are performed before the reading and

...uld need to swap places are the two byte groups "8f 06 28 30 2e" and "8f 06 2a 30 5a" near byte position 64 of isolinux.bin : fb c0 78 70 59 2e 8f 06 28 30 2e 8f 06 2a 30 5a given that isohdpfx.S has: HYBRID_MAGIC = 0x7078c0fb isolinux_hybrid_signature = 0x7c00+64 isolinux_start_hybrid = 0x7c00+64+4 (One may guess that i will propose to patch the ISO at byte 8444*512+70, if i get a "yes" on this question.) --------------------------------------------------------------------- If this is indeed the wrong sequence in...