[syslinux] Dos Boot with syslinux problem.

[MONDON Daniel]

This is important because i will probably need chaining boot and devices
:)

"consoleblank=0" is on the append line.
It is a kernel parameter to don't have blanck screen (default option
when not using energy management).

I test without success to chain.c32 (short test) ... but I succeed to
boot with dos.bss extracted from my usb key on /dev/sdb1 (fat32).

Thanks!
Daniel.


Op 14-6-2011 11:44, MONDON Daniel schreef:
> Hi,
>
> I want to make an USB dual boot DOS - Linux.
>
> If linux is set by default, it is ok.
> If DOS is set by default, it doesn't start.

I'd recommend adding the CHAIN.C32 "program" to your Syslinux. Basicly 
copy it to the same location as your SYSLINUX files, and adapt
syslinux.cfg:
You're not mentioning which DOS you're using, and if that DOS supports 
FAT32, which is most likely used on your USB flash drive.

replace your DOS section by:

label dos
     com32 chain.c32
     append freedos=kernel.sys

(or "append msdos=io.sys" I guess.)

Some documentation for CHAIN.C32 is located at 
http://syslinux.zytor.com/wiki/index.php/Comboot/chain.c32

> I've set DOS on the USB key (OK), and take dos.bss with dd command (dd
> if=/dev/sdb of=./dos.bss bs=512 count=1).

I'm no Linux expert but guess your USB stick is /dev/sdb ?
After you put DOS on it (kernel + shell + bootsector, optionally a 
"config.sys" text configuration file and "autoexec.bat" text boot 
script) actually boot your system from the USB stick.
If that works you should be able to dump the bootsector into a file as 
you did above. However the CHAIN.C32 way seems easier as in both ways 
you're stuck with an extra file :)

> Syslinux version = 4.02.
>
> My Syslinux.cfg is:
> prompt 1
> timeout 50
> default dos
> # not needed for dos test
> DISPLAY Menu.txt
> console 0

I've only used very simple Syslinux configuration files, no idea what 
the CONSOLE keyword is for.

> label dos
> 	kernel /dos.bss
>
> label TCL
> 	kernel /bzImage
> 	append boot=/ initrd=/tinycore.gz kmap=fr-latin9  text
> consoleblank=0
I guess my email client is wrapping lines in a wong way? A separate text

CONSOLEBLANK=0 seems odd, might be a lack of syslinux knowledge on my
part.

> Nothing is done after menu.txt display when power on: only display
some
> 3 unreadable characters...

You should see the "BOOT:" line near bottom of screen I guess, to allow 
you to make a choice? If not, that CONSOLE 0 thingie might be the cause.

If you prefer using arrow keys and menu selections instead of defaults 
or typing entries, then the HDT project has a  "syslinux.cfg" which you 
can can use as inspiration or adapt.
http://hdt-project.org/raw-attachment/wiki/hdt-0.5.0/hdt-0.5.0.img 
(1.44MB floppy, using FAT12 with long filenames).

More complex (syslinux) menus I lack experience with, my needs are much 
more limited.

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