I'm writing this at the point of annoyance. Maybe I'll find a fix in a minute or two. I took an Acer Revo out of service as an HTPC. It was dual boot Win 7 and Ubuntu 12.04 LTS. I applied all Win 7 updates. Fine. Stupid, but fine. I applied all Ubuntu 12.04 updates. Fine. Not even stupid. It offered me Ubuntu 14.04 LTS. I said to go ahead. I almost never do version upgrades, out of fear, but I didn't have much to lose. And everyone always says Ubuntu version upgrades are smooth as silk. Negative observation one: version upgrades take more real time than re-installations. (But they should take less of my attention and care, a win.) Negative observation two: I thought that the slow upgrade process could happen while I was asleep. Yes, but not in one night: there were three steps in the middle that required me to answer a question. It would have been better if the questions had been moved to the beginning or the end. Fedora does that. Negative observation three: It all appeared to work. The updater disappeared from the screen (a little odd). top(1) showed no remnant. So I rebooted. Now I have the prompt: grub rescue> which means I have nothing, not even Win7. I don't think that I can type anything useful into that prompt. Obviously the third is the lulu. The fact that I am using LTS should indicate my risk aversion. I will fix this but I will remember.
On 2015-08-09 11:11 AM, D. Hugh Redelmeier wrote:
So I rebooted. Now I have the prompt: grub rescue> which means I have nothing, not even Win7. I don't think that I can type anything useful into that prompt.
Revos have an EFI bios, right? I used to get this all the time on my Samsung Chronos, until I blew away the dual-boot and put it back into legacy (aka "working") BIOS mode. Boot-Repair <https://help.ubuntu.com/community/Boot-Repair> on a bootable USB stick will likely fix it. Under certain circumstances, Windows updates will routinely destroy grub, so keep this stick handy. cheers, Stewart
On 08/09/2015 12:09 PM, Stewart C. Russell wrote:
On 2015-08-09 11:11 AM, D. Hugh Redelmeier wrote:
So I rebooted. Now I have the prompt: grub rescue> which means I have nothing, not even Win7. I don't think that I can type anything useful into that prompt. Revos have an EFI bios, right? I used to get this all the time on my Samsung Chronos, until I blew away the dual-boot and put it back into legacy (aka "working") BIOS mode. No need for this drastic action. I've dual booted Ubuntu with Windows using EFI without a problem.
Boot-Repair <https://help.ubuntu.com/community/Boot-Repair> on a bootable USB stick will likely fix it. Under certain circumstances, Windows updates will routinely destroy grub, so keep this stick handy. Yes, boot repair is an excellent tool. The other route is to boot off of a Ubuntu live cd, click on try Ubuntu and mount your drives to /mnt. Chroot to /mnt and try to to reinstall grub. Look for errors and correct them.
Cheers, Randy
cheers, Stewart --- Talk Mailing List talk@gtalug.org http://gtalug.org/mailman/listinfo/talk
-- Even philosophers will praise war as ennobling mankind, forgetting the Greek who said: 'War is bad in that it begets more evil than it kills.' Immanuel Kant
| From: Stewart C. Russell <scruss@gmail.com> | Revos have an EFI bios, right? No, this is pretty old. | I used to get this all the time on my | Samsung Chronos, until I blew away the dual-boot and put it back into | legacy (aka "working") BIOS mode. Useful lore. | Boot-Repair <https://help.ubuntu.com/community/Boot-Repair> on a | bootable USB stick will likely fix it. OK. I'm partway into getting a USB stick for Ubuntu 14.04.3. Negative observation four: ubuntu mirrors are inconsistent. <http://releases.ubuntu.com/14.04.3/> and <http://mirror.pnl.gov/releases/14.04.3/> are not the same as <http://nl.archive.ubuntu.com/ubuntu-cdimages/14.04.3/release/> but it is close enough to be confusing. ubuntu-14.04.3-desktop-amd64.iso is in the first two but not the last. (I usually go to a separate mirror for the .iso and the SHA256SUM) Negative observation five++: although the .iso is only 1G, the Ubuntu Startup Disk Creator said my 4G USB stick was too small. It even said that my 8G stick was too small until I tried enough times and ways. And then, after perhaps 10 minutes, it asked for a password to install the bootloader (why is that more special than formatting the drive?) and then said that it failed to install the bootloader. Probably this 5 year old bug: <https://bugs.launchpad.net/ubuntu/+source/usb-creator/+bug/859539> You can see from #6 that I hit this before. The virtually secret log ~/.cache/usb-creator.log isn't helpful. Seems to be some kind of dbus timeout. the logfile seems to never be emptied! I have entries from 2013! So I invoked usb-creator-gtk from an xterm, with secret flag --alow-system-internal Now it won't work because the USB partition /dev/sdb1 is mounted. I cannot unmount it with sudo umount /dev/sdb1. Ejecting makes it unavailable. dd'ing a couple of megs of zeros to /dev/sdb leaves it unperturbed. The final trick was to format the USB drive with the desktop's formatter and not have usb-creator-gtk do the formatting. My guess is that there was some race between useb-creator-gtk and "the desktop". This stick is now nicely bootable. I booted it, installed boot-repair on the stick (why isn't this part of Ubuntu?), and ran it. The result worked -- I could boot Ubuntu 14.04 from the hard drive! The Grub menu was a mess but it was correct. I fixed that from within the installed system. Negative observation 6: The updated-to-14.04 system had some ugly console messages during booting and they didn't go away. Putting one into google, I got a hit in German and guessed what it meant. Apparently HAL isn't used any longer and one of its udev rules (70-something) didn't follow modern standards. The cure was to "apt-get remove hal". How would a normal user figure this out? | Under certain circumstances, | Windows updates will routinely destroy grub, so keep this stick handy. I booted Ubuntu 12.04 after Win 7 updates. So that isn't a good excuse this time.
On 15-08-09 11:11 AM, D. Hugh Redelmeier wrote:
I took an Acer Revo out of service as an HTPC. It was dual boot Win 7 and Ubuntu 12.04 LTS. [snip] I applied all Ubuntu 12.04 updates. Fine. Not even stupid.
It offered me Ubuntu 14.04 LTS. I said to go ahead. I almost never do version upgrades, out of fear, but I didn't have much to lose. And everyone always says Ubuntu version upgrades are smooth as silk.
You jumped over 3 other releases in between. One of which would have been another LTS release. I have done upgrades in Ubuntu when I used to run it and I usually had no problem. In my case I would do a series of upgrades when I only two or three releases behind the current one. If I am too far behind then I would go the route of a fresh install. You are jumping up by four releases and you can find some programs were replaced by other programs which can complicate the upgrade process in some situations.
Negative observation one: version upgrades take more real time than re-installations.
Yes, they often can.
Negative observation two: I thought that the slow upgrade process could happen while I was asleep.
I prefer to do the updates during the day so I can keep an eye on it. There are extra questions that can be asked of you during an install that would bring the process to a halt until an answer is provided.
Negative observation three: It all appeared to work. The updater disappeared from the screen (a little odd). top(1) showed no remnant. So I rebooted. Now I have the prompt: grub rescue> which means I have nothing, not even Win7. I don't think that I can type anything useful into that prompt.
This could be one of a few issues. It could be a failed update to the grub bootloader, it could be the Windows update changed the boot partitions or removed the grub bootloader, or possibly a UEFI related boot issue. If (or, rather when) Windows update messed with the bootloader it usually makes it so the system boots straight to Windows. Seeing a grub prompt means that is not the case here. You can go in to the BIOS of your computer and disabled UEFI boot. I ran in to an issue with it on one of my systems. If that isn't the case you may be able to issue some commands at the grub prompt to get the system to boot. I don't know if things are the same with grub 2 but in grub 1 you would use four commands. "root", "linux", "initrd", and finally "boot" to get the system up. For example: root (hd0,1) linux /boot/vmlinuz-<insert-kernel-version-here> initrd /boot/initrd.img-<insert-kernel-version-here> boot The root line would point to the drive and partition containing the linux kernel and initrd files (what you know often know as /boot when the system is running). The linux and initrd lines can take command line completion so you can hit the tab key to see which kernel and/or initrd files are available. The last word "boot" takes no arguments. It uses the information from the first three commands and attempts to boot your system. -- Cheers! Kevin. http://www.ve3syb.ca/ |"Nerds make the shiny things that distract Owner of Elecraft K2 #2172 | the mouth-breathers, and that's why we're | powerful!" #include <disclaimer/favourite> | --Chris Hardwick
| From: Kevin Cozens <kevin@ve3syb.ca> | On 15-08-09 11:11 AM, D. Hugh Redelmeier wrote: | > I took an Acer Revo out of service as an HTPC. It was dual boot Win 7 and | > Ubuntu 12.04 LTS. | [snip] | > It offered me Ubuntu 14.04 LTS. | You jumped over 3 other releases in between. One of which would have been | another LTS release. Actually, the LTS update path is from 12.04 LTS to 14.04 LTS as one step. There was no LTS between these. Perhaps less visible is that the first time migration is suggested is when 14.04.1 LTS was released, not 14.04. So no, what I did was purely by the book. Ubuntu understands and promotes the LTS-only approach | > Negative observation two: I thought that the slow upgrade process could | > happen while I was asleep. | | I prefer to do the updates during the day so I can keep an eye on it. There | are extra questions that can be asked of you during an install that would | bring the process to a halt until an answer is provided. Quite. That should not be required. | > So I rebooted. Now I have the prompt: | > grub rescue> | This could be one of a few issues. It could be a failed update to the grub | bootloader, Yeah, not good. | it could be the Windows update changed the boot partitions or | removed the grub bootloader, No: LINUX booted after the last time Windows was booted. | or possibly a UEFI related boot issue. No: no UEFI on this old BIOS. | If (or, rather when) Windows update messed with the bootloader it usually | makes it so the system boots straight to Windows. Seeing a grub prompt means | that is not the case here. Window frequently invents new ways not getting along with Linux, often related to booting. Many of the newer and more mysterious ones involve UEFI. For one thing, all systems need to share /boot/efi. Thanks for the grub hints (not quoted). Grub is a complex, powerful, and idiosyncratic tool doing a confusing task. And since it usually works we have little incentive to learn of its commands. It turns out that the "grub rescue>" prompt isn't totally useless. Most of the Grub machinery isn't available, but there is enough that one might be able to climb out of the hole.
On 15-08-13 08:53 AM, D. Hugh Redelmeier wrote:
Actually, the LTS update path is from 12.04 LTS to 14.04 LTS as one step. There was no LTS between these. Perhaps less visible is that the first time migration is suggested is when 14.04.1 LTS was released, not 14.04. So no, what I did was purely by the book.
Ubuntu understands and promotes the LTS-only approach
I just felt safer stepping through all the versions between where I was the where I wanted to be. Mainly this was from when I had been on Fedora. Might be easier if they properly support jumping from LTS to LTS.
It turns out that the "grub rescue>" prompt isn't totally useless. Most of the Grub machinery isn't available, but there is enough that one might be able to climb out of the hole.
Under grub 1 some built in commands/features let you get grub to boot the machine either after a kernel update or a typo slipped in to grubs boot menu. I can't recall having ever used a grub prompt to get a machine to boot since I was forced to start using grub 2. I may be partly lucky. It may be due to my trying to avoid touching the grub.cfg file now that grub 2 made its boot configuration files so complicated compared to the ones used with grub 1. -- Cheers! Kevin. http://www.ve3syb.ca/ |"Nerds make the shiny things that distract Owner of Elecraft K2 #2172 | the mouth-breathers, and that's why we're | powerful!" #include <disclaimer/favourite> | --Chris Hardwick
participants (4)
-
D. Hugh Redelmeier -
Kevin Cozens -
Randy Jonasz -
Stewart C. Russell