grub can't see linux\no boot menu in Win7 - linux

I have both windows and linux installed.
I created a new partition but got Grub error:UNKNOWN FILESYSTEM on restart. Then I used windows recovery CD and Bootrec/fixmbr command to get Grub menu back.
But now I don't see the boot menu.laptop simply boots into windows, also I am unable to boot from any other CD or USB

You need to reinstall grub on the boot sector. If you use Ubuntu, there is a very easy way to fix it with Ubuntu's live CD using the boot-repair tool.
I'm not sure if this will work with other Linux distributions but It's worth trying.
If you can't boot from CD or USB you should check your boot priority in the BIOS. Or try to get to boot selection menu (usually by pressing F12) and choose CD\USB over there, anyways, the answer here is in the BIOS and not related to the grub

Related

Create EFI-stub boot entry from Windows

I use Linux kerne EFI stub to boot. Now I have run into an emergency, because I have lost my UEFI boot entry and I am stuck with Windows.
Is there any possibility to create UEFI NVRAM boot entry for Linux kernel?
I have managed to create it, but without kernel args (like: root=PARTUUID=....) and Linux is not booting without them.
Is there a way how to create boot menu entry from Windows 10 with CLI args?
One solution could be:
Mount the ESP partition under windows.
Create a startup.nsh script to pass kernel parameters
Create boot menu entry which points to the startup.nsh
One way you can resolve this:
You can run any live linux OS, chroot to your still existing installed Linux Distribution, and reinstall grub, which will re-add Linux to the boot menu alongside Windows.

I can not access my ubuntu in dual boot mode

I had installed ubuntu 18 in my acer aspire. Then i installed windows 10 in dual boot mode. After installing the windows i can not access the ubuntu. The grub loader is not shown.
And there is no way to access my ubuntu.
I even tried to change the path of bootloader to ubuntu in cmd.
But no success. Please help me out.
check this link: https://askubuntu.com/questions/602602/cant-access-ubuntu-after-creating-dual-boot
"YOUR COMPUTER BOOTS DIRECTLY TO WINDOWS
This is a common problem and if you do not get a GRUB menu , re-installing or repairing grub will NOT HELP
Every BIOS is different, it might look like one of the following pictures:
UEFI 1
UEFI 2
Notice the "UEFI Boot Option Priority" or "Boot Option Menu" . Usually Windows is the default and Ubuntu (or as in the second picture elementary OS) will be an option.
Once you select Ubuntu on the UEFI boot menu you will then get a grub menu. You should be able to boot either Ubuntu or Windows from the grub menu.
Another issue that could make the system boot directly to Windows (without even showing the GRUB menu) is if either Windows took hold of the boot manager or after installing Ubuntu, the EFI partition was not properly configured for Windows. To solve this, simply go to Windows and open a terminal, then type the following (Need Administrative Privileges):
bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi This will configure the Windows Boot Manager to take into consideration the GRUB Boot Manager. This could still happen even after running the Boot Repair from within Ubuntu. So making sure that Windows reads the Ubuntu EFI partition will solve it."

Difference between wic and hddimg format in yocto

I have generated a core-image-minimal image for my Intel board in Yocto.
Looking into tmp/deploy/images folder they are many images.
I flashed *.wic image using dd command on USB and it created two partitions ( Boot and Platform ) and allowed only to perform a live booting without allowing it to install on the hard disk of the board.
I then flashed *.hddimg on the USB using dd command. It only created a "boot" partition which has rootfs.img, syslinux and EFI folder.
Booting using USB provided me an "Install" option, which installed on the board and when I rebooted after installing, it displays "No bootable media found"
Using bootable image there are two partitions in the hard disk. Why it is not booting..
Steps followed:
Created an minimal yocto image using "bitbake core-image-minimal" command
Flashed the USB using the dd command.
sudo dd if=tmp/deploy/images/intel-corei7-64/core-image-minimal-intel-corei7-64.hddimg of=/dev/sdb
Clicked on install and typed “sda”
The installation was successful and when I tried to restart by removing the USB Drive, it says “No boot options found. Please install bootable media and restart."
What is the mistake I am doing here.
Which image to choose and when..
There was not much info about online, so I asked this question in the intel community and here is the response of that:
Generally a .wic image is intended to be installed directly to its final destination, whereas an hddimg is for evaluation and installation elsewhere.
By default meta-intel .wic images only have an EFI bootloader, and will not boot via legacy BIOS.
An hddimg will have both an EFI bootloader and the syslinux binaries that let it boot from legacy BIOS.
On startup with your installer USB image do you get a light gray screen with four options? If so it is booting via legacy BIOS.

Black Console after automated Debian UEFI install

I try to build a reproducible automated build environment based on Debian 8.1 Jessie.
I created a boot iso image based on a netinstall image and put a preseed.cfg file in int for automatic installation.
I managed to get it bootable with BIOS and UEFI and can install a KDE Developer Debian in VMWare Workstation 11 fully automated.
I have also a server iso image to install a debian Server with Jenkins, both with BIOS and UEFI Boot.
But after the installation, the Version with UEFI Boot shows a black Screen when started.
I can blindly log in, start the gui with "startx" and see my installed xfce desktop. When i quit xfce the console is usable and visible.
I tried suggested bootparameters "nomodeset" and "vga=Linux" that i found with google to no avail.
I also tried to debug the boot prozess, to find out which command leads to a blank screen, but i did not find the right place to delay the processes at bootup so i can see when the messages dissapear (quiet bootparameter was removed :-)
I also tried to reset the console to no avail.
Can anybode point me to a tool that does the same "switching" like X so the console is useable?
Can anybody give me some hints how to debug the bootprocess to find out which command is causing this behaviour?
I dont want to install X because this should be a headless server system later.
I managed to get my system to boot using the kernel command line modprobe.blacklist=vmwgfx, or placing 'blacklist vmwgfx' in /etc/modprobe.d/*.conf
I assume it is some bug in the vmwgfx module, however as this workaround works for me I have no immediate need to investigate further.

how to install linux OS from iso

Two questions, first question is, I want to start using Linux (the Lubuntu distro) as my operating system. I currently have Windows 7 but I don't want to dual boot or run Lubuntu in a virtual machine (which is what I've been doing).. I want to just uninstall Windows 7 and make Lubuntu my OS. Would I be able to do that with the Lubuntu ISO image file that the developers have on their website?
Second question is, I have a Windows 7 CD (which I used to upgrade from Windows Vista to 7). Once I make Lubuntu my only OS, am I able to switch back to Windows 7 with that CD? Do I just run the installation from the Windows 7 CD?
First question; Yes this is possible, you'll want to burn the ISO to a USB stick, then boot from your USB stick. Lubuntu will have an easy installation wizard from the live USB.
Here's a great guide for it.
Second question; You will not be able to do it directly with that CD, as having Vista as the main OS is a prerequisite for that CD to work. If you have a Vista installation CD laying around, then you can install that first, then do the Win7 upgrade.
I'll answer for you second question. You can do it.
But I not perfectly understood your first question. Would you like download an .iso file and install system from it?
P. S. Sorry for my English
There is no option of uninstalling windows.
Your best option, if you don't want to use windows anymore is to backup all your data and format the drive. The formating can be done via the ubuntu installer.
Steps:
1. backup all your data from the drive(partition) you will be formating
burn the iso to a cd/dvd
insert the cd/dvd into the cd/dvd drive and restart your PC
select boot from cd/dvd (by default the cd booting is on, but you may have to enable it in bios)
install ubuntu(the installation guide will guide you through the process)
enjoy Ubuntu
PS: you may want to consider intstalling ubuntu on another partition, this will enable you to choose the OS when you boot your PC

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