Trying to make my new Acer Aspire laptop dual boot with windows 8.1.

[geezer]

Two thoughts:

SteveRiley--Linux and Windows expert--maintains there is no harm done in disabling secure boot; and not much benefit in not disabling it.

Another thought: When Secure Boot is enabled, as you noticed "grubx64.efi was not trusted." That's why we have that other mysterious executable: shimx64.efi. It is allowed, it gets around Secure Boot by simply passing control to the real McCoy grubx64.efi. Here, read all about it:
http://askubuntu.com/questions/34236...64-and-shimx64
That's why you will see grubx64.efi and shimx64.efi both always included together in the UEFI GRUB files for ubuntu (= Kubuntu) stored here (in your Kubuntu root directory): /boot/efi/EFI/ubuntu.

You have made real progress; basically you solved it. It would be nice NOT to have to click through so many screens, though, right? On my rEFInd, I see it in the UEFI firmware menu, I click it, I get a list of things it thinks it can boot for me, I choose from that list, click, and go. But you have basically whipped it.

You might consider what you can do. Can you get into Kubuntu and re-install GRUB from there? Will that place Kubuntu-GRUB as #1? Or, can you run efibootmgr, see the BootOrder, see rEFInd and/or ubuntu in it, and use man efibootmgr to change that BootOrder so ubuntu is #1 or rEFInd is #1?

It's all up to you!


EDIT, just to clarify my terminology above ...

Your ubuntu GRUB boot files are put in the ESP (usually sda1 or sda2). The ESP is mounted in your Kubuntu root directory at /boot/efi. The top-level directory of that is EFI/. In there is the directory ubuntu. The boot files for Kubuntu are in the ubuntu directory. Thus, you have:
/boot/efi/EFI/ubuntu/grubx64.efi
/boot/efi/EFI/ubuntu/shimx64.efi
and usually a
/boot/efi/EFI/ubuntu/grubcfg
and usually
/boot/efi/EFI/ubuntu/MokManager.efi.

Anything with the extension .efi is a UEFI executable (a program).

Sorry - I wasn't very clear.

When I boot now, I go immediately to the rEFInd boot screen. Choose which I want and click on it. Simple like it used to be. I like it. It has more options that I can choose from than just the desired OSs, which means to me that if something goes wrong in the future either due to an error on my part or something else, I can try and find a fix.

I think I'll go with Steve and leave the Secure Boot off.

I've read a more than one post by him and am impressed with not only his knowledge, but also his patience with those with a lot less expertise than himself. That is very valuable. Recently with this new desktop, I was chatting online with the Powerspec tech staff and trying to get help on bringing up the Windows 8.1 Control Panel. The tech staff person wrote that I should right click on the lower left corner of the screen. I tried that a few times and wasn't getting what he said I should. What I was really doing was left clicking because my mind had told me that I was using my right hand and clicking like he told me to. Simple - Right? After 2 exchanges of his telling me what to do and I replying that I was doing that, about 2 minutes total, he blew and handed me off to another member of the tech staff. I'm standing in from of my computer wondering why he blew so quickly. So I'm waiting for the transfer and thinking about what he wanted me to do and suddenly it clicked in my mind that he was referring to the button on the mouse and not which hand. I felt so stupid since I have been doing what he wanted for decades, but my mind had sidetracked and I couldn't get on the right track until I was waiting and cogitating on what had happened. Well the other support member responded and she had me use a key sequence to do what I wanted, bring up the menu items from which to choose the Control Panel. When you can get a tech person that has the patience to deal with people like me, they are very, very valuable.

[Qqmike]

Sorry - I wasn't very clear.

When I boot now, I go immediately to the rEFInd boot screen. Choose which I want and click on it. Simple like it used to be. I like it.

Ok, I see now, good.

As you probably know, rEFInd can boot by the "stub loader" method. Basically, if it sees a recent kernel, it can boot it directly. That's why you may see some vmlinuz's listed as options by rEFInd now and then--click on one and get that OS booted!

Funny story about your right-left tap dance!

My wife uses 8.1 on her ASUS laptop, I don't, but I must "maintain" :-)
And you are probably up on Windows 10 coming July 29th? I'll post this anyway:
How to reserve your free copy of Windows 10
http://www.cnet.com/how-to/how-to-re...of-windows-10/

Glad you are seeing some light on the booting-thinger.

[SteveRiley]

Btw, your Protective MBR is there (in your GPT) in case you did want to boot your PC in the older legacy-BIOS-MBR mode.

Sort of. Principally, the protective MBR is there to prevent utilities that don't recognize GPT from accidentally modifying the partition table. However, if an operating system knows how to perform GPT-based booting using BIOS services, the first sector of the protective MBR must contain the first-stage boot loader. Note that in this case, the computer is still booting into GPT mode.

More: https://en.wikipedia.org/wiki/GUID_P...BR_.28LBA_0.29

[SteveRiley]

SteveRiley--Linux and Windows expert--maintains there is no harm done in disabling secure boot; and not much benefit in not disabling it.

I think I'll go with Steve and leave the Secure Boot off.

Good call. Secure Boot adds a brittle layer of complexity and doesn't address the kinds of threats typical desktop users face. You aren't exposing yourself to additional risk by disabling it.

I've read a more than one post by him and am impressed with not only his knowledge, but also his patience with those with a lot less expertise than himself. That is very valuable.

*blush* Thank you

The tech staff person wrote that I should right click on the lower left corner of the screen. I tried that a few times and wasn't getting what he said I should. What I was really doing was left clicking because my mind had told me that I was using my right hand and clicking like he told me to... suddenly it clicked in my mind that he was referring to the button on the mouse and not which hand.

Hey -- that's a valuable story. It certainly makes clear that more precision with instructions is important. "Click the right mouse button on <blah>" has no ambiguity, whereas "Right-click on <blah>" now seems like it's open to misinterpretation. Thanks for pointing this out!

[geezer]

Also, I do not want to overlook thanking Qqmike for his valuable assistance. I don't know if I would have had the fortitude to continue on this quest without his very helpful information. The wealth of information you provided was what kept me going in this trek. Just Googling various things gets lots of web pages, a few of which really contain useful information. Being able to converse with experts like Qqmike makes all the difference.

Again : Thank You.

[SteveRiley]

Indeed. QQ has become a major contributor here for boot related topics and has shown an excellent understanding of UEFI and GPT.

[Qqmike]

geezer: Also, I do not want to overlook thanking Qqmike...

S-R: QQ has become a major contributor here for boot related topics and has shown an excellent understanding of UEFI and GPT.

Thanks, geezer; and thanks Steve.

Yeah, geezer, it helps to have company--moral support--as you work through any involved issue like this. You seem to know a lot of things UEFI, GPT, and related, and now you have a helluva story to tell re your Acer. You probably know more than many, maybe even most, people around here and elsewhere BECAUSE many people--even capable techie types--are avoiding the UEFI stuff, as they are happy and satisfied with their Legacy/BIOS mode working well for them.

I avoided the UEFI, also, forever, until this year when I built my own UEFI desktop PC, with the Asus H97-Plus board, and literally forced myself to understand some UEFI+GPT. SteveRiley was inspirational in getting myself going on it.

I'm rather limited though -- I only know some principles (like in my Study Guide I linked to above), the ASUS firmware on my motherboard, the Kubuntu installer, GRUB 2 EFI, and now some rEFInd basics. That's about it -- limited basically to just what I've done.

Anyway, thanks, again, you guys.

[Qqmike]

This is about the third time I've run across this fact about Acer laptops:

I recently got a new Acer Aspire V5-131 sub-notebook ... In order to install Linux from a bootable USB stick I need to be able to get to the Boot Selection menu, but on Acer systems with UEFI firmware, this is a bit tricky. The Boot Menu key (F12) is disabled by default, so I first have to boot to the BIOS Setup Utility, by pressing F2 during the power on or reboot cycle. Then in the Main setup screen there is an option to enable "F12 Boot Menu".

http://www.zdnet.com/article/testing...mint-and-more/