Serg008, I am sorry, but I cannot donwload file. Can you put the file (Lenovo ThinkPad T420_1.52 (83ET82WW)-83uj33us_nWL_.rar) on again, please?
I modified the BIOS dump you provided (LENOVO-5ECN33WW(V2.03).rom) - WLAN\WWAN whitelist check was patched. Now you must to flash the modified BIOS (backwl.bin) from a pure DOS environment. (as I wrote above).