hi i'm about to upgrade systems. yesterday i got https://www.zytor.com/pub/syslinux/Testing/6.04/syslinux-6.04-pre3.tar.xz in order to upgrade 6.04-pre1 version. i first was upgrading a usb-disk which was booting smootly with a simple configuration. i changed the EFI installation in /EFI/BOOT: efi64/efi/syslinux.efi (UEFI bootloader for EFI X64 (x86_64) firmware) ? /EFI/BOOT/bootx64.efi efi64/com32/elflink/ldlinux/ldlinux.e64 ?> /EFI/BOOT/ldlinux.e64 i did not touch sysls64.cfg after this action, the bootdisk was not recognized any more by uefi system. i just replaced syslinux-6.04-pre4 bootx64.efi by the old version syslinux-6.04-pre1 and the bootdisk was detected and booted again. size of pre1 version: 200992 B size of pre4 version: 182728 B have fun juerg oehler aka SwissGeorge