PANIC: Failed to find HD boot partition.

Before trying the repair wizard on the ESXi 3.5 CD, I backup-ed all VM's to another machine over the network using an Ubuntu Live CD, how to mount the VMFS store:

• In the software sources, enable the Universe library and reload the packages
• Open a terminal: su
• apt-get install vmfs-tools
• mkdir /vmdir/
• vmfs-fuse /vmdir/ /dev/sda3 (look up your sda, in gparted f.e.)

Also useful to know to fasten the backup:
- Mounting a Samba share to a dir:
apt-get install smbfs
sudo mount -t smbfs -o username=usernamePC,password=ShareAccessPassword,workgroup=MSHOME,gid=smb,uid=$USER,fmask=770,dmask=770,rw "//DEVMACHINE/Share with Spaces" /createdDir

So, after creating a backup, I tried the ESX 3.5 repair wizard, wich is useless, it re-installs ESX and leaves the VMFS store unallocated.

I then just installed ESXi 4 (that formats the full disk)

Second problem: I started VSphere update client, when scanning for updates I get:

The scan operation has failed... Check the logs.

The problem wasn't very known on the internet, so I just reinstalled a second time. Surprisingly the problem disappeared and updates where installed correctly.

Then I just installed VMware converter on the backup PC to re-import the VM's to the ESXi server in the new VMware 7 format.