I am following the following tutorial: Dual boot Surface Pro with Ubuntu?

When I want to create my custom bootloader I need to edit a grub script (among other ones) called 25_custom. But it's not there, I checked it with cd / <enter> sudo find iname "25_custom"

I tried to see if the contents of 25_custom where somewhere else, so I used grep -rnw . -e 'bkpbootx64.efi'. The string is tied to the Windows efi file. The only thing that grep returned where the results from the (downloaded) tutorial on my hard disk.

I could create the file by myself, and copy/paste what the tutorial says about it, but I don't know if that would work. I'm a bit scared to do it, because a previous mistake led me to try to repair my Surface for 10 hours.

So could someone explain what is going on? Edit: it seems 25_custom is created by boot repair, which is not needed to use in 14.10. So now I'm wondering where I'd need to place the code of 25_custom, if at all.

Note: the tutorial about the theming part is only on Github

  • thank you for your findings! Do you have a surface pro 1 or 2 or 3 model version? Per wikipedia, the first two models are distinguishable by the CPU speed; surface pro 1 is 1.7GHz (mine), surface pro 2 is 1.9Ghz, and surface pro 3 is any of 1.5 (i3), 1.7 (i7), or 1.9Ghz (i5). – AnneTheAgile Nov 29 '14 at 19:24

So it seemed that Boot Repair is creating the 25_custom file. This file does not get created when installing 14.10, so in order to create the boot theme, a small change to the tutorial needs to be made.

After some testing I found out how to fix it by grepping on the string "class windows"

It showed that in etc/grub.d/30_os-prober are two entries with the string class windows. If you change the second one (which also has osprober-efi as a string that the other doesn't), then you'll change the boot title of windows. It used to show up as "Windows Boot Manager" and I changed it to "Windows". Here is what I actually replaced in the 30_os-prober file.

It used to be: '$(echo "${LONGNAME} $onstr" | grub_quote)'

I replaced it as: '$(echo "Windows" | grub_quote)'

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