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On a new Samsung laptop with Windows 8 pre-installed I installed Ubuntu. I'm not an expert at all, I've just followed various instruction available in the web. Now, if the OS manual selection is on CSM OS it will boot Ubuntu, giving me the option of booting Windows (loader). but if I press that, it will tell me that the boot is corrupted and I can't go on. If I re-boot and select Ubuntu it boots it normally. Now, if on the other hand the OS MANUAL SELECTION IS ON "UEFI" OR "UEFI AND CSM OS", it will start Windows 8 automatically. So, basically, I have to manually change it every time I want to switch from Ubuntu to Win 8 and vice versa, which is time consuming and little annoying. Now, I repeat, I am very ignorant about these things, I just follow instruction carefully but I don't know the language at all. I've already tried boot repair in Ubuntu (didn't work) and as well I've tried Windows boot recovery (or something like that) when is giving me the options:

  • Ubuntu
  • Ubuntu advanded options
  • windows 8 loader
  • etc

I sense that, may be, I will have to re-install Ubuntu. But I've spent 4 hours trying to install it, every time I was trying to boot from a DVD or USB it was immediately booting Win 8, I was changing and changing the settings in UEFI (reading hundreds of threads and tutorials on-line) before, eventually ) and without being sure of the way I was doing it) being able to install it. Bottom line, I'd love to keep both Windows and Ubuntu cause I need them both and would like to be able to choose between the 2 without having to change the settings every time. Thanks a mil for your help. Fabrizio

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marked as duplicate by Web-E, AgentCool, Stephen Myall, qbi, Eric Carvalho Mar 7 '13 at 0:36

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

i have sad updating...I am now writing from windows8 because ubuntu is not booting anymore. it still give me the option if I have csm os but when it starts, i can only see the ubuntu screen and it stops... i can move the narrow for about 1 sec and then it blocks, end of the story, i can only force-switch off the laptop... thanks in advance for your help... fabrizio –  user137943 Mar 5 '13 at 23:54
You can start here - help.ubuntu.com/community/UEFI or here. But As It is samsung, there was a news about hard brick of device when trying to install linux on Samsung UFEI systems. Don't know whether there is any fix.Be cautious and update UEFI/BIOS first. –  Web-E Mar 6 '13 at 4:36
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2 Answers 2



UEFI and Compatibility Support Module OS

If ubuntu start with CSM, it mean you installed it as bios boot, while win8 is uefi boot. If you want boot twice from grub, or uefi menu of your board, you must convert ubuntu from bios to UEFI. If boot repair has failed, it mean you have not fullfilled every pre-requisite to install UEFI boot

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Concerning the Samsung firmware bug, see Matthew Garrett's blog post on the subject. In brief, it's possible to brick recent Samsungs even from Windows. There was a fix for the most common path to creating a brick in Linux, but that fix won't prevent all such problems in Linux, and certainly not in Windows.

Unfortunately, this means that, at the moment, the only way to be sure of not bricking a recent Samsung laptop is to run no OSes in EFI mode. This means re-installing Windows or converting it to boot in BIOS/CSM/legacy mode (not an easy or well-documented task). Given the OP's current Linux booting problems, I'd say that it's best to just start over with both OSes. The trouble is that you'll need a retail Windows disc to install Windows in BIOS/CSM/legacy mode, although you should be able to use your current serial number, if you can borrow a disc with the same version of Windows you have installed. (The serial number should be accessible from one of the information dialog boxes in Windows, but I don't have details handy, offhand.) You'll need to completely wipe the partition table and convert it to a Master Boot Record (MBR) format. I recommend using GParted or parted for this: Select Device -> Create Partition Table in GParted, or mklabel msdos in parted.

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