Recently I bought an asus X501A laptop containing win8.
Installing slackware 14 from usb I found the HD contained gpt partitions. Figuring these all pertained to windows, which I don't use, I deleted everything and created a standard linux partition table and installed slackware.

But there are problems. Many utilities do not work when asked to write to disk, complaining that it is gpt and they cannot deal with it.

Is this situation fixable? Preferably by completely removing whatever remains of that gpt partition structure, or do I have to create a gpt partition table and reinstall slackware?

Thanks anyway, but never mind. I tried removing the corrupt gpt table with gdisk, but succeeded only in defining the entire disk as gpt, so I have to reinstall anyway.

For the record, the way to handle that situation is with gdisk's extended option 'z' (zap GPT partition table). Since the main GPT table is at the end of the disk, wiping the protective MBR and backup table at the start of the drive doesn't get rid of GPT.

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The situation has since become more interesting. The evidence suggests a deliberate plot by Microsoft to prevent using a non-windows OS. I carried out the following operations on this machine:
1) As stated earlier, I made a usb install of slackware 14 after deleting every gpt partition with cfdisk, and found that nothing would write to disk because still gpt.
2) Attempted to reinstall slackware from usb but found that the usb boot option had vanished from the uefi bios (which calls itself Aptios, and is by American Megatrends Inc).
3) Contacted Asus and received from their Technical help a procedure to access usb boot involving repeated pressing of the Esc key rather than F2 which enters Aptios directly. This did not restore the original usb boot option in Aptios, it gives an alternate access to it.
3) Reinstalled slackware after setting up a gpt partition table for it using gdisk. When I finished the install and pressed Ctrl-Alt-Del to reboot, it entered Aptios and stopped, displaying Aptios' main screen. Accessing the Boot screen, I found that now the option to boot from HD had disappeared, and I could find no way of restoring it. Finally, I chose the only likely looking option, Restore Defaults. The result? The third and last boot option, from the network, disappeared, and I now have no boot options whatever, and no means of creating them.

I can see that the loss of the usb and network boot options could have resulted from my wiping the original gpt partition set, if it was that those boot option procedures were stored on the HD and not in the motherboard. But I cannot equate the loss of the HD boot option with wiping those original gpt partitions, because slackware booted successfully from the HD after I made the first install, so plainly the HD boot option code was not kept on the HD.

On the strength of that I contacted Asus tech help again, recounted my experience as I have here, and stated that I infer, from the progressive 3 stage loss of functionality in this Aptios uefi utility, that Microsoft contracted American Megatrend to deliberately code Aptios to do this if windows 8 was removed from the machine, and contracted with computer manufacturers that they essentially keep quiet about it. Asus neither confirm nor deny my inference, but have repeatedly said they cannot give me the information I have asked for (to restore Aptios to its original condition), and claim that linux may be incompatible with this hardware.

I doubt that last item because I have a functional slackware 14 installed, its just such a pain to boot it that I have no inclination to use it (I have to insert the slackware usb, repeatedly press Esc, choose Boot from USB and when Slackware's install begins, type in the command to boot directly from the HD).

Asus have now offered to restore the machine to its original state if I return it to them. But I see little point in doing that if I can't install a linux that will boot automatically when I press the Power on button.

So my question, has anyone achieved that happy state with this Asus X501A, preferably with slackware, and preferably with win 8 deleted, but I'll accept a dual boot and a different distro if I must.

I believe that most of your problems are caused by UEFI. ASUS and many other computer manufacturers are now using UEFI instead of BIOS firmware. Unfortunately each company's implementation of UEFI can be different and some are better than others.

There are a few things to be aware of when dealing with UEFI.

• Boot choices are stored in NVRAM variables. If the variables are changed or deleted you may lose boot choices.
• UEFI is only able to boot disks if they contain an EFI System Partition (FAT16, FAT12 or FAT32).
• Instead of a boot sector, UEFI loads a "boot loader" UEFI application program (file name ending in .EFI). Default "\EFI\BOOT\BOOTX64.EFI".
• In order for UEFI to boot them, removable disks must have boot loader file named "\EFI\BOOT\BOOTX64.EFI" in an EFI System Partition.
• The UEFI firmware may not provide a flexible way to change the default boot device or file. You may have to use other programs to modify the NVRAM variables to change the boot choices.
• UEFI supports a command shell, but not all manufacturers provide that. It may be built into the firmware or in the hard disk EFI System Partition. You download and install a command shell if it is a version compatible with your computers UEFI firmware.
• Windows usually installs its boot loader to the EFI System Partition in "\EFI\Microsoft\Boot\bootmgfw.efi" and "\EFI\BOOT\BOOTX64.EFI".
• Computers using UEFI might also support BIOS booting using a Master Boot Record (non GPT partition table).
• You can use BIOS booting with a GPT for Linux (but NOT for Windows).

An EFI system partition is a primary partition containing a FAT12, FAT16 or FAT32 file-system. It has a special partition type to indicate that it is an EFI system partition. Although the specification does not limit the number of EFI System Partitions on a disk, there is usually only one. The EFI System Partition (ESP) contains EFI boot loaders in the "EFI" directory. The "BOOT" directory under "EFI" contains the default boot loader file. The default boot loader file is "BOOTX64.EFI" or "BOOTX32.EFI" depending on 32-bit versus 64-bit UEFI firmware. There are some 32-bit UEFI implementations but they are unusual. Other directories under "EFI" contain boot loaders and files from other companies. For example "\EFI\Microsoft"

Your computer may have contained an EFI System Partition. ASUS may have put some UEFI utilities such as the EFI command shell in the EFI System Partition. If you deleted that partition you may have lost important programs needed to configure and maintain your computer. Deleting the EFI System Partition prevents UEFI from being able to boot the hard disk.

You may find it easier to use the BIOS booting for Linux, since Slackware does not come with a UEFI boot loader. When you are booting from removable media, keep in mind that most media supports BIOS booting, and only some discs support EFI booting. The Slackware DVDs and CDs only support BIOS booting.

It may be necessary to enable "Legacy" or "BIOS" booting in your computer's setup. If you don't see the boot choices you expect, check to see if there is a setting to enable BIOS booting.

Your computer's UEFI firmware may provide two boot choices for the same removable device (DVD or USB disk). One option boots using BIOS and the other option boots using EFI. In order to have an EFI boot option, a removable device must contain an EFI System Partition with the "\EFI\BOOT\BOOTX64.EFI" file.

On a CD or DVD, the EFI System Partition is a special "El-Torito" EFI image containing a FAT file-system. EFI does not support booting normal CD/DVD boot images. Slackware CDs and DVDs do not yet contain an EFI boot image, so they can only be booted in BIOS mode. The fact that you can "see" the "\EFI\BOOT\BOOTX64.EFI" file on the CD/DVD does not mean that it can be booted by EFI. EFI does not usually support ISO9660 and it can't "see" the normal files on a CD/DVD.

You can boot the Slackware CD/DVD in BIOS mode and then install Slackware to a hard disk for EFI booting. To do that, you have to install an EFI compatible boot loader (GRUB 2 or ELILO). You must have an EFI System Partition in an MBR or GPT partitioned disk.

When do you have to use UEFI? If you want to boot Windows from a partition on a GPT disk then you have to use UEFI (and a 64-bit version of Windows).

When can you use BIOS? You can use BIOS if you are booting Windows from a partition on a MBR (non-GPT) disk. Windows can still read GPT disks even when it is booted from an MBR disk.

If you are primarily concerned with Linux then I recommend booting Linux using the BIOS mode of your computer. If you use a GPT then you will have to install the boot loader to the protective MBR that is at the beginning of the GPT.

If you want to dual boot Windows and Linux then consider the size of your hard disk. For hard disks less than 2TB (2048GB) you can use a normal MBR partition table and BIOS booting. Make sure that you boot the Windows Setup Disk using BIOS booting (not EFI) to install Windows for BIOS booting. Many manufacturers do not supply a Windows Setup Disk. Your manufacturer's restore disk may only support EFI booting and may only install Windows to boot using EFI. After it has been installed you can't change Windows from EFI booting to BIOS booting (or BIOS booting to EFI booting).

If your hard disk is over 2TB and you want to dual boot Windows and Linux from that hard disk, you will have to use UEFI booting. You must create an EFI System Partition (or let Windows create it). You must boot the Windows Setup Disk using EFI and not BIOS. After Windows has been installed it will only boot using EFI. Note that you can still boot the Slackware CD/DVD to install Slackware. Just make sure that you install an EFI boot loader to boot Slackware. The Windows boot loader cannot "chain" to other EFI boot loaders. To dual boot, you have to chain from the Linux boot loader to the Windows boot loader. You can also use programs like rEFInd to provide a boot menu. Your computer's firmware may allow selection of the boot loader, but that is usually inconvenient.

Some computers have UEFI booting that only supports Windows and not other operating systems (Linux). In that case you may have to use BIOS booting with Linux. Also, Windows may change the UEFI NVRAM variables or files to make Windows the default UEFI boot loader. Some people have reported that they need to rename or replace the Windows boot loader files in order to keep the default boot loader from changing. I don't know if these problems are unusual or common.

Microsoft has made some unfortunate choices about how they will support some recent changes in PC hardware and firmware. Whether one considers that a plot is open to debate. Certainly, Microsoft has not made it easier to dual boot Windows and Linux. Here are some of the Microsoft decisions that I dislike.

• Windows UEFI boot manager cannot chain to another EFI boot loader (APPLICATION BOOTSECTOR won't do that)
• Booting Windows from a GPT requires UEFI
• Booting Windows from a GPT requires 64-bit
• WHQL requires support for secure boot and making secure boot the default
• 64-bit Windows requires signed drivers (unsigned drivers won't run except with debug boot options)
• OEM product keys stored in NVRAM of hardware
• Separation of "Home" and "Professional" Windows features
• Forcing Windows Starter Edition onto NetBooks and killing Windows XP on NetBooks
• 32-bit Windows never fully supported PAE (more than 4GB of RAM) as 32-bit Linux does
• Support for tape backup dropped from Windows Vista onward (before Vista CDs/DVDs not supported)
• Windows 8 boots before displaying boot menu then re-boots computer to boot something else
• Microsoft is not upfront about what UEFI NVRAM variables Windows changes or when
• Making Windows desktop less configurable and less usable from Windows XP to Vista, to Windows 7 and now Windows 8
• Pushing Windows Modern UI on desktop PCs and making it hard to use the old start menu and desktop
• Lack of any tools or support for moving existing Windows to different hardware
• Screwing purchasers of Vista Ultimate by dropping features and making Windows 7 Ultimate upgrade very expensive
• Not supporting upgrade of Vista Ultimate to Windows 7 Professional after removing most differentiating features

Those are just my complaints as a user. My list of complaints as a software developer could fill a lot more space.

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Have you tried booting legacy bios?

Thank you very much, Erik_FL, for such extensive information on this subject. Truly, ignorance was bliss, and now I'm totally depressed at the extent of this problem. Where are those happy days of yore when I gaily consigned Xp, Vista and 7 to oblivion and installed Linux in their places? I guess now I'll take advantage of Asus offer to restore the computer to its original state and start over, with considerably more caution.

I think the general test, of whether a plot lies behind anything that disadvantages any individual or group, is to ask the question, "who profits from this, and how?".

You should be able to change to legacy bios in bios menu.

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Ironically it seems that nobody profits from the poor implementations of UEFI and the horrible Windows 8 user interface. PC sales continue to decline.

All the "experts" predict that portable devices will replace desktop PCs. I think that they are missing the fact that higher performance desktop PCs can't be replaced by portable devices. Perhaps desktop PCs will go back to being a computer enthusiast and business product. That might not be a bad thing.

I haven't used windows since Xp, but I've been told that Microsoft seem to have forgotten the thing that brought them their monopoly, making every program appear similar and have the same basic menu set for the user to work with. Maybe that is because they consider converting linux infidels to their religion more important than keeping faith with their faith.

I worked as a computer programmer long ago, 60s and 70s. All IBM machines, 1400, 7094 and 360 series; and an OS was nothing but a series of macros for I/O, no internet, etc. Even back then, I thought computers were the greatest toy ever invented. Taken it up again in my dotage, now couldn't conceive of living without my pc. The convenience of scripting nowadays, wonderful, compared to everything then in punched cards, debugging by poring over core dumps and patching the program directly in machine code.

Not sure if Aptios offers that option, I don't have the machine with me at the moment, but certainly I will check it out.

Slackware did install from usb, and I believe it to be operational, but its such a pain to boot into it that I never bothered to check it properly, took to haggling with Asus instead to recover those vanishing boot options. If it is operational, there is also the possibility of using a usb boot loader. Slackware offers an option of creating such during the install process, and, though I've never used such, I believe its purpose is to boot the system directly from the HD when this does not occur automatically. If so, that would reduce the current boot ordeal to merely pressing Esc and Enter, which I could also live with rather than the weeks of work this problem seems otherwise to entail.

Would you mind if I quote you, in full or in part, on another forum that is not related to computers.?

I had to get a new laptop and proceeded to wipe Win8. Then, the GPT/MBR, 2 or 3 times. I finally reformatted the hard drive to GPT format, with a Protective Grub MBR.
All I get is an unusual prompt: [bold] GRUB 3: [/bold]
and I don't know what to do with that.

So, time limitations have me booting from one of 3 USB devices with Linux Mint. I am biding my time, hoping the Linux developers will be able to come up with an easier solution to this problem,

I quoted in full vs snipping, due to the age of the thread.

I don't mind if you quote me. I have pretty much done the same as you, avoiding UEFI as much as possible and hoping for the situation to improve. If you would like help with your GRUB boot problem, please start another thread.

Thanks, Erik. I'll do just that, this weekend, with a little luck.

For what it's worth I recently installed Linux Mint on a bare machine, i.e. one that had no Windows pre-installed.
The mobo is an ASUS P8Z68-V/ProGen3 which has what looks like an EFI BIOS.
In my case I think what I ended up with is a GPT disk that boots in BIOS legacy mode. (i.e. from an MBR, not via the UEFI boot feature.)
How did I do this? Almost by accident.

First though I must say that I am running a 64 bit version of Linux. I don't think 32bit versions can do GPT without a recompile.

Even though my disk was only 1TB (1000GB) and MBR partitions would have worked, I WANTED a GPT disk so that I could have more than 4 partitions.

So I booted a live CD, and ran GPARTED. I then told GPARTED to create a GPT disk.
Once that was done I created the following partitions:
Partition#...Label....Size....type..."Flags"...Purpose
1............EFI......200MB...Fat32...BOOT*....For UEFI to store boot loaders etc. Should also contain a 'directory' called 'EFI'
2..........grub_bios...5MB....none....??.......for grub part 1.5. Having this allows grub to store the IPL in the MBR, and the rest of the
................................................code in an easily accessible place.
3............BOOT......20GB....ext4....none....For storing various linux kernel images. I also created a subdirectory there called 'efi'
................................................to mount the EFI partition on.
4............swap........8GB....linuxswap none....Use this for all the various linux'es I plan to install.
5............home......200GB....ext4
6............MINT......20GB....ext4
7............FEDORA....20GB....ext4
8............DEBIAN....20GB....ext4

*Setting the BOOT flag is GPARTED's way of making this partition an 'ESP', EFI System partition with the partition type that tells the UEFI firmware that this is the partition that holds the boot loaders etc.

This works in the usual way. Grub runs, gives me a menu, boots the os I want. When I install another OS, I run update-grub etc.

So the bottom line is:
1. If you have a 64bit OS you can use GPT disks. I am not sure if you need GPT support in firmware, i.e. UEFI. You might not.
2. GPT disks can boot in MBR mode.
3. I don't see any advantage to booting in UEFI mode frankly. Of course if you are running Windows8 you have to, but for any other OS why?

pgmer6809