After I had installed CentOS 7 as the only OS on a HP z230 workstation in UEFI boot mode, I got this message before booting. It was actually the last of three errors:
error: failure reading sector 0xfc from 'hd0'.
error: failure reading sector 0xe0 from 'hd0'.
error: failure reading sector 0x0 from 'hd0'
Boot would resume from the hard disk after a timeout, but the pause was unacceptable and would worry users.
A search showed many articles like this but none solved my problem. I tried various things: refreshing grub.cfg, disabling the CD/DVD (thinking it might be trying to read the optical drive), checking if having the ESP in a EFI system partition in a RAID1 array was disallowed. (I figured out how ESP can work with RAID1, and its limitations, but that's for another blog entry.) None of my experiments worked.
However the linked to web page alluded to turning off Secure Boot so I went into that part of the BIOS setup. I found that it was already turned off but there was a setting there for Legacy Boot which was enabled. So I turned it off to see what would happen. Lo and behold, the error messages ceased, and UEFI boot worked as expected. Also the Boot Order menu stopped showing a Legacy section.
Since debugging the innards of the GRUB2 loader is beyond me, I can only surmise that the presence of Legacy Boot entries in the BIOS makes GRUB2 try reading the sectors in question but since the disk is formatted with GPT partitions and UEFI is in force, the sector reads fail, for some definition of fail. Maybe somebody can figure out the significance of the sectors 0xfc, 0xe0, and 0x0.
error: failure reading sector 0xfc from 'hd0'.
error: failure reading sector 0xe0 from 'hd0'.
error: failure reading sector 0x0 from 'hd0'
Boot would resume from the hard disk after a timeout, but the pause was unacceptable and would worry users.
A search showed many articles like this but none solved my problem. I tried various things: refreshing grub.cfg, disabling the CD/DVD (thinking it might be trying to read the optical drive), checking if having the ESP in a EFI system partition in a RAID1 array was disallowed. (I figured out how ESP can work with RAID1, and its limitations, but that's for another blog entry.) None of my experiments worked.
However the linked to web page alluded to turning off Secure Boot so I went into that part of the BIOS setup. I found that it was already turned off but there was a setting there for Legacy Boot which was enabled. So I turned it off to see what would happen. Lo and behold, the error messages ceased, and UEFI boot worked as expected. Also the Boot Order menu stopped showing a Legacy section.
Since debugging the innards of the GRUB2 loader is beyond me, I can only surmise that the presence of Legacy Boot entries in the BIOS makes GRUB2 try reading the sectors in question but since the disk is formatted with GPT partitions and UEFI is in force, the sector reads fail, for some definition of fail. Maybe somebody can figure out the significance of the sectors 0xfc, 0xe0, and 0x0.
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