The code, 0x80, means the first HDD.
There are commands to boot a specific partition boot sector (instead of loading the boot code in the MBR, for example), but this is not our case.
The command is simply chain-loading to the MBR of your first HDD. Since the system successfully boots by using this code, this suggests that the BIOS recognizes such drive as the first HDD, which is not exactly the same as saying that this is the first device in the boot priority list.
This means either that your BIOS seems to be misconfigured, or that it has some bug, or some CMOS / battery issue.
As I said before, you might want to review the boot priority settings (which is not exactly the same as having this HDD as first / bootable one). For example, you might have the network (e.g. for network booting by means of pxelinux) with a higher priority than the first HDD, which is not what you want / need.
Another issue to consider (although, less likely in this case, I believe) would be whether your firmware is really a BIOS, or a UEFI one. That's a whole different matter.
There are commands to boot a specific partition boot sector (instead of loading the boot code in the MBR, for example), but this is not our case.
The command is simply chain-loading to the MBR of your first HDD. Since the system successfully boots by using this code, this suggests that the BIOS recognizes such drive as the first HDD, which is not exactly the same as saying that this is the first device in the boot priority list.
This means either that your BIOS seems to be misconfigured, or that it has some bug, or some CMOS / battery issue.
As I said before, you might want to review the boot priority settings (which is not exactly the same as having this HDD as first / bootable one). For example, you might have the network (e.g. for network booting by means of pxelinux) with a higher priority than the first HDD, which is not what you want / need.
Another issue to consider (although, less likely in this case, I believe) would be whether your firmware is really a BIOS, or a UEFI one. That's a whole different matter.