Tried to upgrade from 6.5.3 to 6.6 and won't boot up after reboot

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  • 2 weeks later...
  • 4 weeks later...
On 1/9/2019 at 4:28 PM, said:


Try this, it worked for me for an identical error, on the flash drive edit syslinux/syslinux.cfg and add root=sda to the boot option you're using after initrd=/bzroot, e.g.:


label Unraid OS
   menu default
   kernel /bzimage
   append initrd=/bzroot root=sda

Johnnie, thank you for posting this! 


My situation is a bit different as I'm running Unraid under ESXi, which isn't supported, but has done exactly what I need it to do for years.


In my case, everything works perfectly using ESXi 6.0 and ESXi 6.5 but as soon as I tried upgrading to ESXi 6.7 I kept getting the "VFS: cannot open root devise "(null)" or unknown-block(0,0): error -6" message.


I tried everything I could think of and had basically decided that ESXi 6.5 was the highest I could use while keeping Unraid.  I added the " root=sda" on each of the append initrd lines, rebooted the VM, and it booted up perfectly.


Honestly, I have no idea what this does or why it would make any difference at all, but it fixed booting an Unraid 6.6.6 VM in ESXi 6.7



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  • 4 months later...

I just ran into this issue as well.


I have a very old system built for a customer from nearly 10 years ago now.  It is only ever used as a file server so there was no real reason to touch it.  Well, parts finally started to fail (not the motherboard or processor but the drive cages).  The customer was not interested in upgrading anything except for the unRAID OS version.  I went to update it and of course nothing booted after 6.2.4.  As soon as I put 6.3.5 on the USB drive and attempt to boot I would get the above mentioned error.  I updated the BIOS on the board but that solved nothing.  So some google-fu later I find this thread and the suggestion to add "root=sda" to the syslinux.cfg.  That seems to have worked on the OLD Biostar A760G M2+ board with a Phenom II X4 in it.


Not sure what in the kernel between 6.2.4 and 6.3.5 made it stop booting but the "root=sda" trick works fine on this old build.

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  • 8 months later...
  • 1 year later...
  • 9 months later...
On 8/22/2021 at 9:59 AM, timstephens24 said:

This just happened to me after a reboot on 6.10.0-rc1. Easy to add root=sda in the syslinux.cfg, but saw there was a post on it so just wanted to bring it up as something that's still occurring (though it seems rare).


This also happened to me updating to 6.10.2 (I reset back to 6.9) and then again when coming to 6.10.3.

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