Multiboot goes to GRUB prompt after upgrading to Ubuntu 18.04

#1
I had a multi boot setup with Ubuntu 15.10 for a couple of years with no problems, but after upgrading to Ubuntu 18.04, I get the GRUB prompt when trying to boot Ubuntu.

I have Windows 7 and Windows 10 on Disk 0 and Windows XP and Ubuntu on Disk 1. Both disks are BIOS setups (non-UEFI). I installed Ubuntu 18.04 (and GRUB2) on Disk 1, Partition 2. I can boot from either Disk 0 or Disk 1 (as selected in the BIOS). Disk 0 is set up with 4 boot entries (Win 7, Win 10, Win XP, and Ubuntu). From Disk 0, all three Window options work as they always did, but selecting Ubuntu takes me to the GRUB prompt. Disk 1 is set up with 2 boot entries (Ubuntu and Win XP). From Disk 1, Win XP boots fine as it always did, but selecting Ubuntu takes me to the GRUB prompt. Note that I deleted the original Ubuntu entry on both Disks and then added it.

The next thing I did was to boot from a Live Ubuntu CD and updated the MBR on Disk1 to point to the GRUB bootloader on Disk 1, Part 2. When booting from Disk 1, the GRUB menu now comes up with the GRUB menu. I can get to the bootloader (with all 4 options) on Disk 0, the Win XP OS on DIsk 1, Part 1, and Ubuntu on Disk 1, Part 2. These all work fine from the GRUB menu. If select the bootloader on Disk 0 and then select Ubuntu, it goes to the GRUB prompt.

I have seen some other folks complaining about getting to the GRUB prompt after updating to a newer version of LINUX, so I don't think the problem is specific to something in my particular setup.

Any help would be appreciated.
 
#2
I'm having a very similar problem.

I'm running a small server with 5 HDs. Unfortunately, I cannot specify the boot disk. So, I installed EasyBCD on an internal SD-card from where I'm booting Windows 10, Windows Server 2012 - both on different disks - and some ISO-Images residing on the SD-Card. On another disk I have installed Debian 9.5 and Ubuntu18.04. I tried everything I found on the web to boot into these Linux distributions - without success at all. It just goes to a GRUB prompt, same as described by macycat above. If I, however, configure the server-HW only with die Linux-Disk, a Grub 2.02 beta 3-5 boot menu shows up and booting into either Linux version is no problem. Seems, that EasyBCD is not really compatible with Grub 2.

So I'm hoping one a day somebody will find out how to manage this. Since I tried since months now, I'm giving up temporarily.
 

mqudsi

Mostly Harmless
Staff member
#3
@macycat it is implied in your post that GRUB is installed to the MBR and not the bootsector. Our recommendation is to always installed GRUB (or GRUB2) to the bootsector of the Linux partition, which greatly increases the reliability of chainloading.

@quasimodoz where was your GRUB2 boot code installed?

Also, please make sure to clarify when you say "it goes to a grub prompt" whether this is a grub2 prompt or EasyBCD's internal copy of grub that is being loaded.
 
#4
@macycat it is implied in your post that GRUB is installed to the MBR and not the bootsector. Our recommendation is to always installed GRUB (or GRUB2) to the bootsector of the Linux partition, which greatly increases the reliability of chainloading.

@quasimodoz where was your GRUB2 boot code installed?

Also, please make sure to clarify when you say "it goes to a grub prompt" whether this is a grub2 prompt or EasyBCD's internal copy of grub that is being loaded.
When I installed Ubuntu, I installed Grub2 on the Ubuntu partition (Disk1, Partition2). Since I normally boot from Disk 0, I added an Ubuntu boot entry there with EasyBCD. When I select the added Ubuntu entry from the Disk 0 (Windows) boot menu, it takes me to the Grub4DOS prompt (I assume that is EasyBCD's internal copy of grub).

I also set up a Windows boot menu on Disk 1 with WinXP and Ubuntu as boot options, so when I boot from Disk 1 (selected in the BIOS), I get the Windows boot menu. If I select Ubuntu from there, I also get the Grub4DOS prompt. Then I updated the Disk 1 MBR to point to Grub in the Ubuntu install. That gives me the full Grub menu with multiple options that all work as expected including chainloading the Windows boot menu on Disk 0 and booting Ubuntu.

Thanks so much for trying to help out here. As I mentioned before, it seems like a number of people are having the same or similar issues.
 
#5
USER=145592]@quasimodoz[/USER] where was your GRUB2 boot code installed?

Also, please make sure to clarify when you say "it goes to a grub prompt" whether this is a grub2 prompt or EasyBCD's internal copy of grub that is being loaded.
How can I check where Grub2 is installed? My installation procedure: Single Disk (to be exact: this is Disk 4 on my HP Micro-Server Gen8 where bays 1,2,and 3 are empty and on die CD-port a SSD with Windows 10 is installed) formatted: Partion 1: 340GB ext4, partition 2: 340GB ext4, partition 3: Linux Swap, rest unformatted. On partition 1 I installed Debian 9 straight forward with default settings, on partition 2 Ubuntu 18.04.1 also straight forward. After that I can boot from this disk either Debian or Ubuntu, but I habe no idea where Grub is residing. Even Windows 10, which resides on the next HD in the chain is listed.

So everything seems to be ok, but i WANT to boot from an internal MicroSD-card for several reasons. Booting from the MicroSD-card into Windows is ok and also 2 other Linux-based "CDs" which are on the MicroSD card. Booting Debian or Ubuntu on the HD fails.

So again, how to check where Grub2 resides and I BELIEVE, that it is Grub from EasyBCD, when I try to boot the HD Debian.
 
#6
I am having similar issues. I am new to EasyBCD and I was not able to do what I wanted. I wanted to provide a bootable partition in addition to the two instances of Win 10 already installed using the win 10 boot manager and then install one of the Linux distros in that partition. When I booted the Linux (Lubuntu) install thumb drive it erased the win 10 manager and installed Grub. I don't want Grub, I should be able to use the Win 10 boot manager, no? I need to have two instances of Win 10 and then one (or more) bootable instances of Linux. Is this possible or no? I'm using a PC with a 500 gb drive and no data or programs until I can make this work.
 

mqudsi

Mostly Harmless
Staff member
#7
Instead of seeing where GRUB is installed (which is hard) you can just run `sudo grub-setup -f /dev/LINUX_PARTITION_HERE` from within Linux to get it installed to the bootsector of the Linux partition, then point EasyBCD to that partition.

@cncman yes, what you are asking for is possible. You need to reinstall the Windows bootloader to the MBR with EasyBCD and then add a Linux entry. See the wiki at EasyBCD for more info on these topics.

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For all trying to dual-boot with Linux, this is a beta build of EasyBCD 2.3.1/2.4 that contains updates to Linux dual-booting and a few other fixes. You can try deleting all existing Linux entries and then recreating them with this build (simply updating EasyBCD does not affect existing entries).
 

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#8
Instead of seeing where GRUB is installed (which is hard) you can just run `sudo grub-setup -f /dev/LINUX_PARTITION_HERE` from within Linux to get it installed to the bootsector of the Linux partition, then point EasyBCD to that partition.

@cncman yes, what you are asking for is possible. You need to reinstall the Windows bootloader to the MBR with EasyBCD and then add a Linux entry. See the wiki at EasyBCD for more info on these topics.

---

For all trying to dual-boot with Linux, this is a beta build of EasyBCD 2.3.1/2.4 that contains updates to Linux dual-booting and a few other fixes. You can try deleting all existing Linux entries and then recreating them with this build (simply updating EasyBCD does not affect existing entries).
The beta build works! I simply installed the beta build, deleted the Linux entry, and then recreated it per the latter part of your instructions, and it now works. Grub2 now loads and gives me all the boot options therein. I did not need to install Grub2 to the Linux boot partition per your earlier instructions, possibly because Grub2 was already installed there?

Thanks so much for the update!
 
#9
The beta build works! I simply installed the beta build, deleted the Linux entry, and then recreated it per the latter part of your instructions, and it now works. Grub2 now loads and gives me all the boot options therein. I did not need to install Grub2 to the Linux boot partition per your earlier instructions, possibly because Grub2 was already installed there?

Thanks so much for the update!