[syslinux] Question of syslinux chainloading

[Lu Wei]

On 2019-4-11 13:29, Lu Wei wrote:
> On 2019-4-10 1:20, Ady Ady via Syslinux wrote:
>>>>> #This item fails
>>>>> label dos
>>>>> menu label MS-^DOS 7.1
>>>>> com32 chain.c32 msdos7=io.sys
>>>
>>> IO.SYS and COMMAND.COM are copied from a Windows98 system on another
>>> computer, which is MSDOS7.1; and BOOTSECT.W98 is from Bootpart tool (I
>>> compared it with the one from my Windows98 system, and I think they are
>>> basically the same except label name, so I use this one), but I think if
>>> io.sys is loaded, boot sector should be of no use. I have tried "boot
>>> BOOTSECT.W98" and "bss BOOTSECT.W98" without success, so I'd like to
>>> jump over it and get to IO.SYS directly.
>>  
>>  
>> Would you please try using the equivalent files for FreeDOS in the USB? You can 
>> see the options for chain.c32 in the Syslinux wiki. There are at least 2 wiki 
>> pages relevant for chain.c32, so I would suggest taking a look at both of them.
>>
> FreeDOS equivalent file of io.sys is kernel.sys, (both use command.com
> as CLI shell), and can successfully boot by:
> com32 chain.c32 freedos=kernel.sys
> 
>> BTW, which exact version of SYSLINUX are you using? Is your chain.c32 from the 
>> same exact package / version? FYI, different versions should not be mixed, and 
>> the options that chain.c32 actually supports depend on the exact version (with 
>> some backward incompatibilities too).
>>
> I downloaded syslinux-6.03.zip from official site,  and extracted all
> files in \bios to H:\syslinux (sub-directory structure not retained to
> reduce path command in syslinux.cfg), except later I found memdisk do
> not honor path command and moved it to root. So they must be same version.
> 
I forgot to say, the error message of "com32 chain.c32 msdos7=io.sys" is:
----------------------------------------
BPB detection (sect): unknown
Booting...
(16 non-text strange characters)
----------------------------------------
Then press Esc can return to syslinux boot menu.
-- 
Regards,
Lu Wei
IM:	xmpp:luweitest at riotcat.org
PGP:	0xA12FEF7592CCE1EA