I have updated the firmware & drivers our R440 & R730 PowerEdge Servers using Dell's Platform-Specific Bootable ISO with no issues, but I'm having issues when updating the R740 servers. I tried using the Dell prebuilt ISO PER740_BOOTABLE_21.12.00.24 and creating them from DRM but get the same errors. When selecting the One-shot UEFI Boot Menu and select my bootable USB. I get this error.

When I try selecting the BIOS Update File Explorer and select bootx64.efi file. I get this error.