Lenovo files only have bios region update, no CSME FW v11.8, those need to be dumped/used for reconstruction or it may not be need at all to program, if corrupted initialization is needed.
Files for whoever wants to try it with a SPI programmer:
EX480 NM-B481 REV 1.0 BIOS DUMP & SCHEMATIC | Lenovo Thinkpad X1 CARBON - Indiafix