Re: simple message under BIOS/CSM/LEGACY

[Pascal]

hi,

Gregory(@syslinux) highlights the PBR :
*"""Well, I'm still just guessing, but some BIOS systems might execute a
PBR (partition boot record) instead of the MBR if one exists and the
partition is marked active. You might need to make sure that there is no
DOS partition table on the system (or at least that none of the partitions
are marked active)."""*

gdisk used for my GPT partitioning installs a protective DOS partition
table, however the only partition present is not marked as active.

regards, lacsaP.

Le lun. 1 août 2022 à 09:53, Pascal <patatetom@gmail.com> a écrit :

> between `start:` and `cli` ?
>
> Le lun. 1 août 2022 à 09:50, SteveSi <easy2boot@gmail.com> a écrit :
>
>> Maybe clear direction flag first?
>>
>> cld
>>
>> ??
>>
>>
>> On Mon, 1 Aug 2022 at 08:40, Pascal <patatetom@gmail.com> wrote:
>>
>>> hi,
>>>
>>> I have a live system with only UEFI boot supported.
>>>
>>> to indicate this to users who have not yet switched to UEFI, I have below
>>> this simple little piece of code (partly found on the internet) that I
>>> compile with nasm and I push onto the MBR.
>>>
>>> it runs perfectly on some PCs and in virtual machine with Qemu, but
>>> refuses
>>> to run on other PCs by displaying either a kind of smiley logo or a
>>> simple
>>> blinking cursor.
>>>
>>> does anyone have any idea or clue about this?
>>>
>>> regards, lacsaP.
>>>
>>> 8<--------------------------------
>>> ; nasm nobioscsm.asm -f bin -o nobioscsm
>>>
>>> bits 16
>>> org 0x7C00
>>>
>>> start:
>>>     cli
>>>     mov si, msg
>>>     mov ah, 0x0E
>>>     .loop lodsb
>>>     or al, al
>>>     jz halt
>>>     int 0x10
>>>     jmp .loop
>>>
>>> halt:
>>>     hlt
>>>
>>> msg:
>>>     db 0x0D, 0x0A, '** Boot with BIOS/CSM no longer supported : reboot
>>> with
>>> EFI/UEFI **', 0
>>>
>>> ;times 510 - ($-$$) db 0
>>> ;dw 0xAA55
>>>
>>