Hi all, old thread but i thought I'd share what i learned the hard way regarding the issue experienced by xrunner and others with the ESALOADER floppy disk not booting.
As far as I can see, the SA *really* wants ESALOADER to be the *only* thing on the floppy....including directory entries.
If you're using a newish Windows OS (I was using W10), it will automatically add a hidden/system folder "System Volume Information" to your floppy. Even the act of just inserting the floppy (without any deliberate read/write action) will cause Windows to inspect the floppy and "helpfully" add the folder if it's not there.
I understand there is a way to disable this behaviour with a registry setting (search for "windows disable system volume info removable media"), but as I had a working WinXP system, i just used it to prepare the floppies - no problems.
I did lots of experiments formatting the floppies and copying the files on different systems (including formatting on the SA). They could all be read on the SA using the file menu so I'm confident it's not a format/drive issue.
FYI I was using the same USB floppy drive on both systems.
Good luck!