Can't get a rom image below 512k?

steven james pyro at
Thu Nov 14 09:01:01 CET 2002


If all else fails, it should be possable to generate an image by just
concatenating the etherboot .elf binary, some padding, and the two
linuxbios.strip binaries together.

recent objdump (that supports i8086 arch) with -D (disassemble all) can
help to see where the pieces should go. Just remember that the top of the
rom will appear at f0000 at boot time in real mode. Once it gets through
__protected_start, you'll be up at the top of memory in i386 arch
(ffffxxxx or in primary linuxbios at fffexxxx). One of these days, I'll
need to write this up :-)


On Thu, 14 Nov 2002, Andrew Kohlsmith wrote:

> > I missed something, is your kernel in the 512k romimage?
> Was.  I've now removed it and have a 64k rom image (no payload, I must get 
> etherboot + IDE into the payload as an elf image [yes, I *have* been scouring 
> the mailing lists!]).
> Incidentally, I'm running as and compiling etherboot 5.0.6 + the 
> IDE boot patch found on the list causes problems:
> $ make
> -DELF_IMAGE  -DPOLLED_IDE -Os -ffreestanding -fstrength-reduce 
> -fomit-frame-pointer -mcpu=i386 -malign-jumps=1 -malign-loops=1 
> -malign-functions=1 -Wall -W -Wno-format -Wno-unused -DVERSION_MAJOR=5 
> -DVERSION_MINOR=0 -DVERSION=\"5.0.6\" -DRELOC=0x400000  start32.S | as  -o 
> bin32/start32.o
> {standard input}: Assembler messages:
> {standard input}:87: Warning: indirect ljmp without `*'
> {standard input}:197: Error: suffix or operands invalid for `ljmp'
> make: *** [bin32/start32.o] Error 1
> I'm going to upgrade as tomorrow and see if that helps.  as sure is a bicky 
> bugger.
> > > Now my biggest concern is that the target board has a 256k flash device. 
> > > I don't think I can fit 512k into 256k.  :-)
> > so you'll need etherboot.
> *nod* -- I got that figured out this evening.  :-)
> > the smartcore-p5 I think builds a 256KB romimage.
> Yes, I was using config.example instead of config.etherboot.  My config file 
> (attached) is currently payload-less, but I am trying to get etherboot+ide on 
> it.
> > I'm intrigued though, how small is your kernel again?
> >
> > Are you sure that a 512KB flash won't work in your board? the address
> > lines might be there.
> heh, the kernel isn't very useful, but the bzImage is 360625 bytes.  Just IDE 
> + serial console ATM (no networking support).  I think it was just over 400k 
> with networking support.
> Is there a location where I can find out what all the options are and what 
> they mean?  I haven't been able to locate any documentation to that effect 
> yet.  Similarly, is there a clear distinction between the Config and config 
> files?  
> Regards,
> Andrew
> Regards,
> Andrew
> _______________________________________________
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> Linuxbios at

-------------------------steven james, director of research, linux labs
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