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I cannot boot into grub, I can see this

Alloc magic is broken at XXXXXX Press any key

but when I do nothing happens. Holding shift doesn't do anything also.

The last time I could use my machine I changed stuff in the /etc/grub.d but I chroot into the system, reverted everything and successfully ran update-grub.

Any help appreciated.

If anyone wondering: Ubuntu 12.04.1, Installation media was (I guess) 11.10, it's an i5-first generation kernel, 4GB RAM, memtest was okay.

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You should run memtest to verify, that faulty main memory isn't the root cause of this. – David Foerster Apr 6 '15 at 19:26

A Boot-Repair Live USB can be used to repair Grub. You can download the ISO from the Ubuntu Wiki. Then, use Unetbootin to create a Live USB from the ISO file you downloaded. After you boot from the USB, the Boot Repair utility will pop up. Just click on the Recommended Repair button, and Boot-Repair will repair Grub for you.

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I did that. Changed nothing. It did give come "advice", but nothing which should prevent GRUB from starting, and nothing which wouldn't be the same since the original installation. – mrs_sheep Sep 3 '12 at 15:01

This is not a software issue, The alloc magic broken error is a result of bad memory chips.

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I have solved this.

After all, i used Rescatux and mainly SG2D to chainboot into my regular system. I then ran update-grub again and was wondering again why it would list everything twice when it occured to me to check the "grub.cfg" (just read, not write!).

I then found out that the supposingly "reverted" changes to the GRUB-config were super-happily alive preventing grub from starting. (I had named the not-working ones with ".n" for "new" assuming they would be ignored (like ".bak"))

SO: is it a valid bug to be posted, that reinstallation of grub does not clear the config dir?

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