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Goal: Install ubuntu 14.04 to my 32gb usb (not persistence/live-usb), and be able to boot with this usb on different computers.

What happened:

1) Used a small 3gb usb and format it to live boot ubuntu

2) Restarted Windows 10 laptop and booted with usb

3) Inserted 32gb usb

4) 3gb usb booted up to GRUB Boot loader

5) Clicked install

6) Chose "Something else"

7) Found by 32gb usb (sdc I believe, sda was my SSD, sdb was the live usb I was booting it off of)

8) Create new partition table, used ext-4, drop down selected "/"

9) Made SURE that the bootloader drop down menu pointed to sdc

10) Successful installation!

Result: If I plug in my USB to the laptop I installed it on, boots like a charm. If I remove it, I get stuck on GRUB command prompt screen. So I changed the boot order menu to: Windows 10 (SSD) -> Ubuntu(SSD), then I realized that Ubuntu boot was written onto my SSD. Checked my theory by putting USB into an older laptop, boot is stuck at flashing "_"

Question: How do I get it so that I can boot Ubuntu with this USB, do I need to redo this whole process or is there another way? And what's the correct process? I obviously missed something.


EDIT: This is the pastebin link from boot repair: http://paste.ubuntu.com/12116317/

sda = SSD on laptop (Upgraded from Windows 8.1 -> 10)

sdb = Small usb used for live-usb

sdc = 32gb usb that has ubuntu installed in it, but cannot boot by itself

  • If BIOS install answer below should work. But if UEFI install you must manually create the ESP - efi system partition as first partition on flash drive when using gpt partitioning. Grub still will not install to anything but sda's ESP. But then you copy /EFI/ubuntu to flash drive and also copy shimx64.efi to /EFI/Boot/bootx64.efi. External devices boot only from bootx64.efi and shim or grub in UEFI mode expect to find a grub.cfg in /EFI/ubuntu. So both folders & files must exist. – oldfred Aug 17 '15 at 15:28
  • @oldfred, my system is UEFI. From your comment to the first answer (http://askubuntu.com/questions/329461/install-grub2-to-usb-drive-in-order-to-boot-to-hdd-installed-ubuntu-13-04-x64-in) in another question, I am still unclear of the steps. May I ask you for a step by step instruction please? I am new to ubuntu. – quidproquo Aug 18 '15 at 01:07
  • Is flash drive gpt partitioned, and do you have an ESP? I have seen installs with MBR but still UEFI. You want gpt partitioning on flash drive and and ESP as first partition formatted FAT32 with boot flag. Some explanation here: http://askubuntu.com/questions/84501/how-can-i-change-convert-a-ubuntu-mbr-drive-to-a-gpt-and-make-ubuntu-boot-from Post details by running Summary report and post it in first post above. https://help.ubuntu.com/community/Boot-Info Then if you still need help I can post details based on your current configuration. – oldfred Aug 18 '15 at 03:35
  • @oldfred, thanks for all your help so far, I ran the tool and provided the link in my original question. What is the next step I should take? – quidproquo Aug 18 '15 at 06:15
  • You have no ESP - efi system partition on sdc. If new install probably easier to start over. Use gparted and create a 200 to 500MB FAT32 formatted partition with the boot flag as first partition, then your ext4 partition for Ubuntu. Reinstall to ext4 partition using Something Else. I have told it to install grub to my flash drive, but it never has and just installs to the ESP on sda. Then you have an ESP on sdc to copy files from sda to sdc. As a UEFI boot system, it will only boot on UEFI systems. If you want to boot on an older BIOS only system, you should install in BIOS boot mode. – oldfred Aug 18 '15 at 14:52
  • @oldfred this is getting off topic but your comment made me to wonder... When I made a Linux Mint live usb a while ago, it was able to boot on both my new UEFI laptop and old BIOS laptop, any reason why it can do that? – quidproquo Aug 18 '15 at 15:08
  • The live installer is a FAT32 but MBR partitioned drive. UEFI is then able to find the efi boot files or a BIOS system finds syslinux boot files in MBR. Some have tried grub in both MBR and efi, but when they get out of sync when only one is automatically updated you have issues. https://help.ubuntu.com/community/Installation/UEFI-and-BIOS – oldfred Aug 18 '15 at 15:33

1 Answers1

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I'm not sure what went wrong for grub to get installed in the wrong place, but you shouldn't need to redo the whole install. grub2-install DEVICE can be used to install grub to any disk.

1) Boot into the system on the 32G ssd

2) Make sure you have the right device for the usb drive by looking at partition tables or something. (I'll call this /dev/sdc, if yours is different adjust commands below accordingly)

3) Run grub2-install /dev/sdc as root to install grub on sdc.

Faxn
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