[syslinux] Patching your own boot-disk from first principles

[Radio Tron]

heh, If you are going to resort to shameless self-aggrandization how can I refuse <g> just kidding! <g> Thanks awfully. Actually, I had posted to the gPXE list and Marty Connor (Etherboot) suggested I try SYSLINUX's memdisk: (gPXE->pxelinux->memdisk->GRUB+IMAGE). The reason for GRUB in the image is because it seems more flexible (I can add a GRUB passwd, and can boot into Windows/Linux on HD/floppy/USB or re-edit the GRUB cmd line and boot anything..

Trouble is, I'm not able to build a proper MSDOS-IMAGE with HD/Floppy emulation
because I don't understand how all this works. The QEMU tip is neat, however I
would like to learn about the inner workings, and use basic tools like fdisk,
dd and perl and not let Knoppix do all the work :p

The "Hacking GRUB" section within the GRUB docs, has the structure of Master
Boot Record, and format of partition tables sections missing.. I tried editing
the defective HD-Image file that Symantec creates, and inserted GRUB stage1 and
fat_stage1_5 at sectors 1, 2. Then I dumped the FAT16 FS that was embedded at
sectors 63-end, mounted that, created /boot/grub and copied stage2 and a
menu.lst file.Also copied stage2 to / and /boot (just to be safe). Then
repatched the Symantec image with the new FS. Then mkisofs, and when i boot I
get: GRUB GRUB GRUB, in an endless stream! Which probably means stage2 is not
loading - but what am I doing wrong???

I also tried stage1, stage2 at sectors 1,2. That works but, at the GRUB
prompt: NULL (<TAB>   lists devices: fd0 fd1.. fd6 hd0, and rootnoverify(fd0);
chainloader +1; boot(fd0) b0rks.. Probably implies that HD emulation is kaput
because stage2 nuked things (exceeds sectors 2-63)

mkisofs -b osboot.img -hard-disk-boot -o osboot.iso ./
Gives me: "Size of boot image is 48132 sectors -> Emulating a hard disk
Warning: image size does not match geometry (48195)"

Should I increase the size of the partition by 63 sectors? I tried
dd if=/dev/zero count=63>>osboot.img but that didn't work because fdisk
osboot.img continues to reports 24066 blocks instead of 24098. I deleted the
partition in fdisk but couldn't recreate it with 24098 blocks.

Quite frankly, I need too much help :) It's better if you guys could point me to the docs. I've already checked out the GRUB docs.. dunno what else to look at.. src may be beyond me..