Dual boot missing windows 10 option

[Ron D]

I am totally new to linux terminology. Anyway I have an old HP slate 500 on which i decided to install Android x 86 4.4 R5. Prior to installing i did create a partition of 5 gigs via windows disk mgmt to save Androidx86 files. I didn't assign it any volume. Then started with installation of Androix86, whenever i clicked on new partition i would get the fatal error bad partition. Somehow i was able to avoid by clicking new partition -> answered yes for GFE or GFI (some option i don't remember the exact name), selected the 5 gig space...it went thru few more menu option and i installed androidx86. It never showed any option that it saw windows ntfs. After installation grub bootloader no longer shows windows. It only allows me to boot to android. I have spent 5 days researching but its just hard to understand grub, sudo, linux terms. Any help would be appreciated.
#iwantwindowsback:-)

[michel thomasius]

Welcome to a steep hill to climb! :)

I had to spend 3 days researching UEFI to wrap my head around this new technology (new to me...), because I was used to booting linux via the older, much simpler MBR methods.

I suspect your windows partition is still there, and working, but you've killed the UEFI boot record for it. So when the machine boots, and reads the EFI partition /dev/sda1 or /dev/sda2, (A: or B: under Windows) it cannot find a suitable entry for Windows, only for Android.

You would need to use a third party boot disc like G-Parted or a Linux Live CD/USB Stick to boot the machine to a suitable running OS, to repair the damage. Alternatively, you could try http://www.ubcd4win.org/, but you would need Windows XP sources and a windows machine to build the CD. So catch-22! ;)

Unfortunately a LOT of learning is involved, and I think you may have picked a hard version of Linux to learn with. I would have played around with Ubuntu for a bit before attempting the move to Android-x86, because Ubuntu is a LOT more user friendly. Android X86 still has some quirks which require more advanced Linux skills. If you don't have those, it will be easy to screw up!

P.S. I am not questioning your intelligence. Its just a case of not being experienced with this sort of stuff. And you only get the experience through going through this sort of pain and finding a solution for it! ;)

[Hypo Turtle]

I disagree; it seems OP is just missing the Windows entry in Grub2 [google for chainload Windows in Grub2 - and you should see what you need to add to grub]

Just to check that Windows is still there and boots; check in BIOS/UEFI if you can boot another boot entry/manager - you should have at least 2 others; 1 is efi shell; the other should be WBM

[Jon West]

It is a good likelihood that you are just missing the windows entry, like another user mentioned. Here is what I have for mine, you should just be able to add it to the grub.cfg file.

menuentry 'Windows' --class windows {

search --file --no-floppy --set=root /EFI/Microsoft/Boot/bootmgfw.efi

chainloader (${root})/EFI/Microsoft/Boot/bootmgfw.efi

}