I boot Linux Distros from USB in a Virtual Machine using a variety of different methods...
1. Use Plop Boot Manager to chain load the OS on the USB Disk.
2. Use the following option in the VM's .vmx configuration file booting a UEFI/GUID partition USB Disk.
firmware = "efi"
For 64-bit OS also add...
efi.use64 = "TRUE"
3. Use vmware-rawdiskCreator to create a meta-data .vmdk for the target disk and manually add the .vmdk to the .vmx configuration file.
I've used all three methods with various Linux Distros however not all methods work with all Distros/Configurations.
