After select volume [n] in diskpartattributes volume clear hidden fails with
Virtual Disk Service error:The object is not found.I found some forum threads which might contain a solution (http://www.sevenforums.com/installation-setup/248241-repair-windows-7-boot-menu-uefi-4.html, https://social.technet.microsoft.com/Forums/office/en-US/cc44af84-f8f2-4fc2-8445-ad34d62ae8f2/problem-clear-hidden-volume-in-diskpart?forum=winservercore), but I can't figure it out and keep my sanity. The world is ready for Q&A quality answer.
I'm using Windows 8 on a Lenovo IdeaPad U410 in the recovery cmd. Windows doesn't boot after installing an Ubuntu dual boot. I just need to do a BIOS update (has to run on Windows) and don't care about Windows. I don't have any recovery media and the issue I'm trying to fix with the BIOS update is not worth buying one.
I can't remember if I every booted windows, I might have just moved initially installed partitions around with gparted. Removing the hidden flag with gparted on Ubuntu 16.04 causes the hidden flag to be removed across reboots, but still be displayed in diskpart.
The output of attributes disk after select volume [n] is
Current Read-only state: NoRead-only: NoBoot disk: NoPagefile Disk: NoHibernation File Disk: NoCrashdump Disk: NoClustered Disk: Nochkdsk [letter]: /f /r /x passed for all 4 volumes and are reported Healthy in diskpart.
After bootrec /fixmbr and bootrec /fixboot which complete successfully bootrec /scanos find 0 Windows installations.