I can confirm upgrading an HP Gen8 Baremetal from DSM 6.0.2 Update 8 to DSM 6.1.3 Update 3 and then Update 4 form DSM 6.1.3 with Jun's Bootloader ver 1.02B !
The Upgrade was straightforward, only changing the bootloader and make the settings from original post, and upload DSM 6.1.3 Update3 pat file !