How to modify grub.conf for Ubuntu partition

Question

I was trying to install Ubuntu 13 on my new lenovo computer with haswell processor and nvidia G750M. I have never installed linux before and learned basic unix commands last week.

I was following a guide: Unable to install Ubuntu on Lenovo Y500

However, I got to the part where I was able to install Ubuntu successfully, but now I can't open it (the screen turns off when it opens).

I need to be able to finish the final steps, in order to fix my issues but I can't seem to locate the partition linux is on, everything is a GPT partition table with no labels when i do fdisk -l :

5) After the install is complete, boot again with your USB and select "Try Ubuntu" and let it boot to the text console.

You will not be able to use this new Ubuntu install until you edit this grub.cfg as well. To do this, first mount this new partition, and then edit the grub.cfg as above in the Ubuntu editor of your choice (vi, nano, etc).

sudo mkdir /mnt/newinstall
sudo mount /mnt/newinstall /dev/sdb8
sudo vi /mnt/newinstall/boot/grub/grub.conf

(Same edits as listed in step 3. Also on my install Ubuntu was on the 8th partition > /dev/sdb8. Yours may vary so check it first!)

** Note the file is write protected, so make sure you use ":w!" to write from vi.

Trying to input those exact commands gives me: /mnt/newinstall is not a block device

I really want to start using Ubuntu but I can't without changing the one line in grub.conf (i think)

Answer 1

Swap the two params of mount command.

Answer 2

The error /mnt/newinstall is not a block device is caused by your giving the parameters in the wrong order.

mount newdevice mountpoint says "mount the device with name newdevice in the directory with name mountpoint".

So what you need to do is change the second command to

sudo mount /dev/sdb8 

Answer 3

fdisk does not work for GPT drives. You can use parted or download gdisk which is the fdisk for GPt drives. I suggest you install gdisk even if you do not use it for creating partitions.

sudo parted /dev/sda units print

sudo gdisk -l /dev/sda

If using the nVidia driver you need nomodeset. From grub menu press e for edit, scroll down to Linux line and change quiet splash to nomodeset. But some new systems also require other boot parameters.

My computer boots to a black screen, what options do I have to fix it?