[syslinux] boot fails on some system

[Jethro Tull]

On Fri, 14 Apr, 2017,  0:05:05 +0000, Ady Ady via Syslinux wrote:
[ ... ]
> 
> Please next time reply to the Syslinux Mailing List email address.
> 
> I am aware that the EXTLINUX wiki page mentions 'cat' as a method to 
> write mbr.bin. The reason for that wiki page to present such command is 
> because the official documentation included to this day in the Syslinux 
> distribution archives is also presenting the same command.
> 
> The suggested command to write to the MBR area is to first _unmount_ 
> all the devices related to the physical device you want to write to, 
> and then execute the 'dd' command as described at:
> 
>  http://www.syslinux.org/wiki/index.php/Mbr#Write 
> 
> Beware: use the correct "sdx" device for your case / OS; writing to 
> 'sda" if the device you are aiming at is a different one will cause you 
> much more problems.
> 
> I would also add the 'sync' command, after dd'ing the mbr.bin file to 
> the desired output device and/or after finishing any write operation to 
> a portable device you are about to disconnect.
> 
> Having said that, there are many reasons for a system to fail to boot 
> correctly, especially when using an external device. Some of them are:
> _ mixing different versions of Syslinux-related files (although, since 
> the device successfully boots another system, this doesn't seem to be 
> the problem);
> _ CHS geometry;
> _ type of connection (e.g. USB 2.0 vs. 3.0)
> _ booting as USB-Floppy (or some other mode) in the BIOS setting while 
> having a different type of device (e.g. USB-HDD);
> _ using a BIOS-based bootloader on a UEFI system while in UEFI mode, or 
> some inverted situation...
> 
> There are many more alternative explanations / possibilities.
> 
> Saying "it fails to boot" doesn't really describe anything useful that 
> would help in narrowing down the problem. We don't know what exactly 
> you actually see on screen (blinking cursor perhaps?), or whether it 
> reboots, or perhaps the connection/port/hardware is not "stable" 
> enough... I'm not saying that one of these is the actual problem, but 
> rather that we lack of enough information.
> 
> I would suggest repeating the procedure with the FAT fs, this time 
> using dd to write the MBR.
> 
> Please note the correct device you are about to write to. Otherwise, 
> you will overwrite the wrong device, making things even worse. Also 
> note that the mbr.bin file shall be written to "sdX" (where "X" here 
> represents the adequate device, and you should replace it with the 
> adequate letter), and it is _not_ "sdx1" (i.e. do not use a partition 
> device when writing the mbr.bin file).
> 
> Regards,
> Ady.

As for replying address I noticed that using the "reply" button lead to a
reply message with "Ady Ady" in the "To" field of hotmail, thereafter I
cancelled and tried "Reply All" and it still showed only "Ady Ady". To get
more details about the actual email address I needed to allow all scripts in
firefox but with hotmail there are dozens and make more that minutes to
display the page. It seems you set your personal email address in the
"Reply-To" field. I just realised that in such cases the email client, even
mutt, ignores the "To" list, and probably "Cc" too. Anyway ...

As for the device file, if you read back my email you'll notice that I indeed
took that care about the difference in naming of devices and partitions in
linux.

That's good you talk about blinking cursor or reboot regarding boot failure.
I had indeed well noted that for booting off the ext partition I always get a
blinking cursor on the upper left corner of a totally black screen and when
trying booting off the FAT partition the computer reboots. I will
nevertheless check the port, though I never noticed any problem like that
with this computer since the beginning I have it, i.e. ~ ten years.

I will repeat the procedure with using dd for writing the mbr and sync
afterwards.