Fedora uses LiveCD or USB to fix GRUB2 boot

After Fedora uses LiveCD or USB to fix GRUB2 boot with LiveCD or USB, it should be clear which partition your Fedora is installed in. the hard disk should be SATA now, then it corresponds to/dev/sda #, # is a number, 1 ~ 4 indicates the primary partition. 5 is... after Fedora uses LiveCD or USB to fix GRUB2 boot with LiveCD or USB, it should be clear which partition your Fedora is installed in. the hard disk should be SATA now, then it corresponds to/dev/sda #, # is a number, 1 ~ 4 indicates the primary partition, and 5 is the logical partition. If you are using an IDE hard disk in a writable environment, it corresponds to/dev/hda #. Www.2cto.com open your Disk utility or Disk unity and find the partition where Fedora is installed. my partition is sda10, so let's take this description below. 1su2mount-t ext4-o rw/dev/sda10/media mount the installation partition of Fedora to the current LiveCD file system. of course, if you are relatively lazy, such as me :), double-click the partition in the file manager and mount it under/media/_ FEDORA. The original Fedora installed on the hard disk at www.2cto.com only hangs the file directory. there is no hardware resource, and nothing can be done. it can only be used to copy/paste data, now, give the resource of the current system to him: 1su2mount-t proc none/media/proc3mount-o bind/dev/media/dev4mount-o bind/sys/media/sys5mount-t devpts/media/dev/pts special look at the instructions above, do not write/dev as/dev/. if this happens, the following error occurs:/dev is not a block device. After mounting, use the chroot command to switch to the original Fedora: 1su2chroot/media3grub2-install/dev/sda of course, the above Command is to say that grub2 is installed on the hard disk MBR recovery boot, if you want to mount it in the current partition for other software to boot it should be: grub2-install/dev/sda10 OK, do the following: 1exit2umount/media/proc3umount/media/dev/pts4umount/media/sys5umount/media/dev6umount/media7reboot. of course, the grub repaired above is the original grub, but grub2 is very powerful, to automatically identify multiple systems, you only need to regenerate the configuration file: 1su2grub2-mkconfig-o/boot/grub2/grub. 20173reboot Congratulations! I encountered some other problems when I was repairing it for someone else. I wrote it down and shared it: first, the partition of this computer is not a simple partition I wrote above, if the LVM and the boot partition sda8 are used, they will be mounted separately during mounting. In LVM, there is a root logical volume group and a swap volume Group, located in/dev/mapper/vg_fedora_root, and/dev/mapper/vg_fedora_swap (this name is defined by yourself, if you use the default system partition for installation, the name is different if it is not manual) 1su2mount-o rw/dev/mapper/vg_fedora_root/media3mount-o rw/dev/sda8/media/boot then mount the resources written above. Second, when the grub2-install is executed, an error occurs: 1 [root @ localhost] # grub2-install/dev/sda2/sbin/grub2-setup: warn: Your embedding area is unusually small. core. img won't fitinit .. 3/sbin/grub2-setup: warn: Embedding is not possible. GRUB can only be installedinthis setup by using blocklists. however, blocklists are UNRELIABLE and their use is discouraged .. 4/sbin/grub2-setup: error: will not proceed with blocklists. network The figure above shows that the embedding area between MBR and sda1 is too small. it should be the default value of 63. if it is 32, this problem will occur, but I run fdisk-lu, the computer is already 63, for unknown reasons. Google did not find the solution or the installation was not possible. later I saw this usage on the wiki and forced installation. 1grub2-install -- force/dev/sda can be installed and started successfully ~