@ erwan.l
Sorry to bother you again but I just wanted to make sure you read the EDIT and specialy the EDIT-2 on my previous post, to make things easier I will Quote them for you here:
EDIT: 4 - I don't know what parameters/settings (if any) you are using on your tool, but it only recognize an *.lz4 as a valid file when it was made with it, just tried several settings and no one was accepted for decompression.
EDIT-2: Bad news my friend, the 10x64-WB.vhd.lz4 made with Clonedisk DO NOT Ramboot, info of heats/sectors per track is not found and then grub4dos selects the tipical 255/63 (wich in fact the source VHD was before compressing it, and allready re-checked with BootIce) and there is a message about partition table invalid or corrupt.
Also I forgot to comment I was on Win7x86 OS when testing the compression and decompression of the VHDs just in case it may be a factor that may have any influence on the issues.
alacran