Some minor additional information: booting from pci-express ssd only fails when the boot-image is configured to allocate space for writing. So the problem seems more than likely related reading/writing and or heavy io with the pci-express ssd during boot time.
Some minor additional information: booting from pci-express ssd only fails when the boot-image is configured to allocate space for writing. So the problem seems more than likely related reading/writing and or heavy io with the pci-express ssd during boot time.