I assume this is you. So, if so, since you are on Arch Linux have you tried to reinstall the Syslinux bootloader?
(As root): syslinux-install_update -i -a -m
syslinux-install_update
script to automatically install the bootloader (-i
), mark the partition active by setting the boot flag (-a
), and install the MBR boot code (-m
)
Since you have a GPT partitioning scheme ensure gptfdisk
is installed if not already or the above root command will fail.
Ensure that /boot/syslinux/syslinux.cfg
actually points to the right partitions (e.g. /dev/sda2) for your specific set-up.