I have pushed syslinux-5 to edge and it made 2 of my boxes unbootable.
It also broke setup-bootable to create new usb disks (it passes args
differently to /proc/cmdline so /etc/init.d/modloop breaks)
Basically, you cannot use syslinux-5 to create any current alpine
If you have made an apk upgrade and run alpine linux from edge, make
sure that you have /usr/share/syslinux/libutil.c32 in your /boot and
that all the /boot/*.c32 files are updated. (copied from /usr/share/syslinux/*.c32)
Also make sure you have a rescue cd/usb handy before you reboot.
Sorry for the inconvenience.