Same issue here on ASUS Zenbook UX301LAA with SSD Raid. For some reason os-prober ignores Windows Boot Manager EFI partition. Looks like the real problem is the EFI test. Here's a syslog entry after running os-prober:
Jun 7 00:00:17 shadow-zenbook os-prober: debug: running /usr/lib/os-probes/mounted/05efi on mounted /dev/mapper/isw_dahhdhgec_ASUS_OS1
Jun 7 00:00:17 shadow-zenbook 05efi: debug: /dev/mapper/isw_dahhdhgec_ASUS_OS1 is a FAT32 partition
Jun 7 00:00:17 shadow-zenbook 05efi: debug: /dev/mapper/isw_dahhdhgec_ASUS_OS1 is virtual device: exiting
Same issue here on ASUS Zenbook UX301LAA with SSD Raid. For some reason os-prober ignores Windows Boot Manager EFI partition. Looks like the real problem is the EFI test. Here's a syslog entry after running os-prober:
Jun 7 00:00:17 shadow-zenbook os-prober: debug: running /usr/lib/ os-probes/ mounted/ 05efi on mounted /dev/mapper/ isw_dahhdhgec_ ASUS_OS1 isw_dahhdhgec_ ASUS_OS1 is a FAT32 partition isw_dahhdhgec_ ASUS_OS1 is virtual device: exiting
Jun 7 00:00:17 shadow-zenbook 05efi: debug: /dev/mapper/
Jun 7 00:00:17 shadow-zenbook 05efi: debug: /dev/mapper/