Syslinux Question & Issues

I THOUGHT I had an old Sandisk Cruzer Micro (1GB) that would not work with UnRAID after I did the usual format - copy AIO distribution - run Makebootable on it,  and it wouldn't boot on the old system I wanted to use it on (an old Intel D865G motherboard).

It just gave a non-descriptive blank screen and "Boot Error" message.

Just for grins, I repeated the preparation process using the v4.7 AIO ... and it WORKED !!

I then tried the v5 AIO again on an 8GB Kingston flash drive ... and the SAME problem ("Boot Error").  Did it with v4.7, and it works !!

Interestingly, if I upgrade the working v4.7's on both of these flash drives to the latest v5RC16c it works perfectly (i.e. just copying bzroot, bzimage, and syslinux.cfg to the flash drives & rebooting).

What I've noticed is this: 

(a)  The Syslinux.exe that's distributed in the v4.7 AIO is 26.5KB (27,136 bytes).  This is the same as the standalone download of Syslinux on Limetech's site.    The Syslinux.exe included in the v5 AIO downloads is 70.5KB (72,192 bytes). 

(b)  The smaller version shows multiple lines of dots when the "Loading bzroot" message is displayed before the boot actually "takes off".    The larger version just shows one line of dots.    Other than this display difference, both seem to work just fine ... except for the boot issue that the newer version has on some older systems.

After noting this, I remembered a few weeks ago when I had decided UnRAID couldn't boot from an old 128MB flash drive I had tried ==> I dug it back out and lo-and-behold it was simply this same issue ... initializing it with the v4.7 AIO did the trick -- it works perfectly as well !!

Is there any reason not to just use the older version of Syslinux when preparing flash drives?

... and/or is there a list that shows which chipsets/motherboards require the older version?

Does Syslinux have any function after the OS is loaded?

Syslinux is just a boot loader and doesn't have any function after OS loaded.

It may be a bug on syslinux that is triggered by old bios... you may use old syslinux without problems or just try to update it (the one on unraid is apparently 4.03), you can get other versions at: https://www.kernel.org/pub/linux/utils/boot/syslinux/

You just need to get two files (from the compressed file you will download) win32/syslinux.exe and com32/menu/menu.c32 then overwrite the ones with same names on root of your flash and then run make_bootable.bat to "install" that syslinux version.

I would just start by trying 4.06 as it is the latest one on 4.x series, you can also try 5.x or 6.x but you also don't need the new features on them anyway...

Edit: Also note you may need some extra files for 5.x/6.x, see:

http://www.syslinux.org/wiki/index.php/Library_modules