I’m facing an issue when PXE booting on PCs with UEFI. The boot fails with the following error:

Kernel panic - not syncing: VFS: Unable to mount root fs on "/dev/ram0" or unknown-block(1,0)
Kernel Offset: disabled
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on "/dev/ram0" or unknown-block(1,0)
This issue only happens on UEFI clients — legacy BIOS boots work fine.

What I’ve tried:
Tested different DHCP boot file options: ipxe.efi and snponly.efi — same result
Tried both latest and older versions of bzImage and init.xz — no change

The DHCP server runs on the same FOG Project server.
My topology is: ESXi Host → Cisco Switch → Client.
Other PCs with BIOS boot normally - but UEFI clients always fail with the error above.

Any ideas what might be causing this or how to fix it?

Thanks in advance!

@george1421 Thank you so much! I enabled portfast on the switch port, and it works on physical PCs.

Kernel panic - not syncing: VFS: Unable to mount root fs on "/dev/ram0" or unknown-block(1,0)
Kernel Offset: disabled
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on "/dev/ram0" or unknown-block(1,0)

But sometimes this error appears even if I haven’t changed anything in the configuration and files. Even if I update or roll back the init.xz or bzImage file to a previous version, it doesn’t help. The only thing that seems to work is setting up a completely new FOG server, but after some time, the problem can come back. How I can find right version or how I can solve this problem? Most time it error on PCs with UEFI

Hello,

I have a problem with getting an IP address after the PXE menu. My FOG Project server runs on an ESXi host. I tried creating a VM on the same host, and it works (both UEFI and BIOS), but when I try on a real PC, I get this error. The network topology is: ESXi server → Cisco Switch → Client.

Starting en01 interface and waiting for the link to come up
udhcpc: started, v1.37.0
udhcpc: broadcasting discover
udhcpc: broadcasting discover
udhcpc: broadcasting discover
udhcpc: no lease, failing
Either DHCP failed or we were unable to access http://ip/fog//index.php for connection testing.
No DHCP response on interface en01, skipping it.
Failed to get an IP via DHCP! Tried on interface(s): en01
Please check your network setup and try again!

I tried many ways, like configuring DHCP on my Windows Server and also using the DHCP built into the FOG Project, but every time it works on a VM, but not on a real PC. On the forums, I read that it could be because of the init.xz file. I tried changing the version, but with some versions I get an error about mounting the root fs.

Also I tried run in on Debug Mode, but i get error:

Unable to mount root fs on "/dev/ram0" or unkown-block(1,0)

I tried two different types of PCs, both with UEFI and BIOS modes. I also checked our firewall and I don’t see any traffic between the client and the server, and nothing is being blocked.