Hi,
You are following wrong upgrade guide. Here is the correct one:
https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/c/sw/gui/config/guide/3_0/b_Cisco_UCS_C-series_GUI_Configuration_Guide_301/b_Cisco_UCS_C-series_GUI_Configuration_Guide_201_chapter_01101.html
Beginning with Release 3.0, the BIOS and Cisco IMC firmware files are no longer embedded inside the HUU as a standalone .zip file. BIOS and Cisco IMC firmware must now be extracted using the getfw utility, which is available in the GETFW folder of the HUU.
To avoid potential problems, Cisco strongly recommend that you use the Cisco Host Upgrade Utility (HUU), which upgrades the BIOS, Cisco IMC, and other firmware to compatible levels.
Please rate helpful posts and if applicable mark "Accept as a Solution".
Thanks, Vaijanath S.