Firefox made a few commits, so I rebased off of latest release.
Let me know what bugs or issues you encounter with it.
Works on Windows 7+ natively
Does not work on XP or Vista stock.
Works on Vista Extended Kernel without needing osver.ini fix. It will 0xc0000005 on first launch but work fine afterwards.
Works on XP with One Core API with these environment variables set:
MOZ_DISABLE_CONTENT_SANDBOX=1
MOZ_DISABLE_GMP_SANDBOX=1
MOZ_DISABLE_GPU_SANDBOX=1
MOZ_DISABLE_NPAPI_SANDBOX=1
MOZ_DISABLE_RDD_SANDBOX=1
MOZ_DISABLE_SOCKET_PROCESS_SANDBOX=1