[syslinux] failing with I/O error when loading Linux kernel

[Jon Martin]

I'm trying to use syslinux 6.03 to boot a QEMU VM.
The config file is very simple:
DEFAULT foo
PROMPT 1
UI menu.c32
LABEL foo
  LINUX /boot/vmlinuz
  INITRD /boot/initrd
  APPEND root=LABEL=ROOT ro

Syslinux starts right and finds the config file (it knows what the label
foo is), but then fails to load the kernel: "Loading /boot/vmlinuz...
failed: I/O error"

I get the same error whether the VM is presenting the disk as virtio or
SATA.  I have tried MBR and GPT partitioning.  I have made sure the ext4
filesystem is made without that new troublesome 64bit extension.  I have
also tried specifying the device instead of using the label on the APPEND
line.

If I tell it to boot /boot/vmlinuks (which doesn't exist) it says "Loading
/boot/vmlinuks... failed: No such file or directory".  This leads me to
believe that Syslinux is able to read the /boot directory but not the
kernel?  I done an MD5 sum on the kernel and the same kernel on a
different machine (which Syslinux is booting just fine) and they match so
it is not a file corruption issue.

The closest thing I have found to a related problem is:
http://www.syslinux.org/archives/2017-March/025654.html

What else should I try?
-- 
Jon Martin 
System Administrator - System Administration 1
Information Services & Technology at University of Alberta
780-492-1662  http://ualberta.ca/IST/