Dual boot with Windows 8.1 on Toshiba Sattelite

I am trying to install Ubuntu 13.10 as a dual boot on a laptop with pre-installed Windows 8.1

After learning how to disable Secure Boot and switch from UEFI boot to CSM boot I managed to boot UbuntU from a USB drive and go through the installation. But when I try to boot the machine from the hard drive it either boots Windows 8.1 (when UEFI boot and Secure Boot are turned on), or just hangs, seemingly trying to boot from Ethernet.

I then tried Lubuntu 13.10, and it did install in the CSM mode. Now my laptop boots Lubuntu when in CSM mode and Windows when in the UEFI.

Another detail: when I go through the installation Ubuntu does not notice Windows 8.1 at all, so I have to choose "Something else" option to avoid erasing Windows.

The laptop is Toshiba P55-A5312, and the BIOS is American Megatrends with Aptio Setup Utility.

I'll really appreciate your help after spending many hours on reading bits and pieces on the Net and trying every variation I could think of. Thanks a lot.

Another data point: I also tried to install Ubuntu 12.04, Mint 16 and Fedora 20 with similar success rate.

For extra info here is the output of the 'parted' command in Lubuntu:

Model: ATA TOSHIBA MQ01ABD0 (scsi)
Disk /dev/sda: 750GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system     Name                  Flags
 1      1049kB  1075MB  1074MB  ntfs            Basic data partition  hidden, diag
 2      1075MB  1180MB  105MB   fat32           Basic data partition  boot
 3      1180MB  1314MB  134MB   ntfs            Basic data partition  msftres
 4      1314MB  373GB   372GB   ntfs            Basic data partition  msftdata
 6      373GB   673GB   300GB   ext4
 7      673GB   683GB   10.0GB                                        bios_grub
 8      683GB   703GB   20.0GB  linux-swap(v1)
 5      741GB   750GB   9572MB  ntfs            Basic data partition  hidden, diag

The reason you are having trouble is that if you install an OS under CSM mode then it's only able to boot in CSM mode. CSM mode is when the computer acts like it's got BIOS. Operating systems then boot from the MBR of a hard drive rather than from the UEFI (fat32) partition. You must install both operating sytems under UEFI or CSM, not 1 one way and the other another. When you install ubuntu it's going to make itself primary boot but you will be able to select windows from the list.

If you are concerned about messing up windows boot ability as many Windows 8 users have, you can always backup your UEFI parition before installing Ubuntu, that way if anything goes wrong you just restore the UEFI data and you can boot into windows like it never happened. I would recommend using DISM for this which is best run from a free tool called WinPE, specifically version 4 which is built using WADK, you can download that from the microsoft website for free, but DISM is also installed on Windows 8 and 8.1 by default, however if you can't boot windows that doesn't do you much good, so I recommend building the WinPE disc. MAKE SURE TO USE DISM, NOT IMAGEX for capturing images, because Dism supports extended file attributes, Imagex doesn't. If you want to do a restore never delete the parition in question, only re-format it.

Using Dism:

Capture a .wim: Dism /Capture-Image /Compress:max /CaptureDir:b:\ /ImageFile:d:\backup.wim /Name:"backup"

Apply a .wim: Dism /Apply-Image /ImageFile:d:\backup.wim /Index:1 /ApplyDir:b:\

Create A WinPE 4.0 iso using Wadk For Windows 8:

Copype amd64 c:\location

imagex /mountrw c:\location\media\sources\boot.wim 1 c:\location\mount imagex /unmount c:\location\mount /commit

MakeWinPEMedia /ISO c:\location c:\location\winpe4x8664.iso

For more information about DISM type "Dism /help" in the Windows 8 terminal...run the comand prompt as an Administrator. You can do so by right clicking the icon and choosing "run as admin" from the bottom bar of the start screen.

I was able to get my Toshiba Satellite C55-A to load Ubuntu 12.04 and support the existing Windows 8.
These were the steps I followed: 1) First I made the bios change you mentioned to boot from USB, then loaded Ubuntu 12.04 from a USB drive. I used gparted using the try it version to get the NTFS partitions shrunk down, then created a new partition for Linux and a swap partition. When I did the install, I discovered that it has to be connected to the internet to get updates or GRUB will not configure correctly (Wired Ethernet). When done it still could only boot into Ubuntu as the Windows 8 GRUB selection didn't work.

2) Once it boots into Ubuntu you can download the boot repair(Wired Ethernet).
http://www.howtogeek.com/114884/how-to-repair-grub2-when-ubuntu-wont-boot/ Here are the commands you need: sudo add-apt-repository ppa:yannubuntu/boot-repair sudo apt-get update sudo apt-get install -y boot-repair boot-repair

3) The next step was to get the driver for the wireless Ethernet "rtl_92ce_92se_92de_8723ae_88ee_linux_mac80211_0012.0207.2013" I found it on this site http://ubuntuforums.org/showthread.php?t=2120170 I was not done however at this point as I was getting compiler errors during the build. I was able to comment out the lines that it was complaining about as it is not supported in new versions. After removing from ~5 files I was able to get a clean build and the "make install" finally worked. Every time I update the system, I end up having to do the make install as it seems to forget about the driver. So keep your directory around with the fixed files. I would love to know how to fix that. Hope this helps.