1

I followed exactly the steps upto flagging the the two partitions using gpart. The 1MB partition flagged as bios_grub has File System grub2 core.img according to picture shown in steps. For my case there is exclamation sign and under File System it is showing unknown. Secondly, ubuntu was successfully installed on my USB. But is not booting (instead it open grub, which i don't know how to install). May be i need to follow the next steps, "Copy the boot and the EFI folders from the Ubuntu ISO file to the boot,esp partition sdx3". Kindly help how to copy these files to partitions. Personal Note: I have already bricked my Google Pixel C while trying to root it. My ultimate goal was to install ubuntu on my rooted Pixel C. My Computer has Windows 10 installed. Laptop is Asus rog 55VW. Window 10 was upgraded automatically by Microsoft from Windows 8. My Hard disk has no partition is a 750Gb SSD. Reading Bios/ UEFI discussion make me anxious about losing my laptop Windows and data. Thanks I am waiting for some guidance.

Muti81
  • 11
  • You need to understand UEFI & BIOS and MBR & gpt. https://askubuntu.com/questions/1130372/dual-booting-win-10-and-ubuntu-18-04-on-two-separate-physical-ssds https://askubuntu.com/questions/1167910/unable-to-properly-boot-linux-from-external-ssd/1167940#1167940 & https://askubuntu.com/questions/913716/dual-boot-on-seperate-drives-best-configuration – oldfred Nov 27 '20 at 14:25
  • Presently I have removed my laptop hard disks. I am booting from Live Ubuntu USB and want to "Full Install" Ubuntu to another USB, that will ultimately work in this laptop without the need to remove hard disk each time I want to use Ubuntu. – Muti81 Nov 27 '20 at 15:34
  • How you boot install media, UEFI or BIOS is then how it will install. With UEFI, drive should be gpt. And if just Linux, you can still use gpt with BIOS boot, but need the bios_grub partition. You will have to boot external drive from UEFI boot menu, like installer and will have to use the drive entry which uses /EFI/Boot/bootx64.efi as all external devices in UEFI mode use that file to boot. – oldfred Nov 27 '20 at 17:52
  • The third option on the page “How to Create a Full Install of Ubuntu 20.04 to USB Device Step by Step” is the easiest method of making a Full install to USB. Simply flash the image file to the USB using Rufus, Etcher or Win32DiskImager in Windows. When done create a new user with password and delete the old one. Yes follow the next steps, "Copy the boot and the EFI folders from the Ubuntu ISO file to the boot,esp partition sdx3" – C.S.Cameron Nov 28 '20 at 03:45
  • The 1MB partition starts as unknown but will eventually change itself to grub2 core.img. – C.S.Cameron Nov 28 '20 at 04:21
  • Is the third option this 'Install Ubuntu from a Pre-built Image File.? This give me another path in case the first method don't work. But first today my main task is some sort of minimum Windows back up. I ask further when i dig into these. But thanks for clearing these steps. – Muti81 Nov 28 '20 at 15:39

2 Answers2

0

The 1 Mb partition flagged as bios_grub is used on systems that are equipped with legacy BIOS's only, when the user wants to use gpt on their boot disk instead of mbr.

If your system is equipped with UEFI and you boot it in UEFI mode, the installer will format the USB flash correctly automatically, creating the necessary efi partition.

Stormlord
  • 6,317
  • This means that my system has EFI Bios and therefore bios_grub partition is unknown is not a problem. – Muti81 Nov 27 '20 at 15:24
  • if above is correct then i need information regarding Copy the boot and the EFI folders from the Ubuntu ISO file to the boot,esp partition sdx3, please. – Muti81 Nov 27 '20 at 16:32
  • The reason for using both bios_grub and boot,esp partitions when building the USB is so the Full install USB will boot off both BIOS and UEFI mode computers. (This is a trick I learned "reverse engineering" mkusb Persistent USB's). – C.S.Cameron Nov 28 '20 at 11:43
0

Copy the boot and the EFI folders from the Ubuntu ISO file to the boot, esp partition sdx3

After step "Wait until install is complete" do not reboot or unplug the target USB.

  • Open the ISO file using Open With Other Application/Open With Archive Manager.

  • Drag and drop the boot and efi folders from the Archive Manager to the boot,esp partition, (sdx3).

  • If you have any problems with permissions, etc, open Nautilus using sudo -H nautilus and try copying again.

Thank you for bringing this to my attention, I will edit the other answer. Please let me know of any other difficulties or if anything else is unclear.

C.S.Cameron
  • 19,519