Just a quick PSA as I was bitten on multiple hosts today:
If you install the new BIOS 2.4.7 on a Dell R740 (and probably R640 as well) and have a NVidia Tesla M10/M20 installed (for example for VDI acceleration) the system will be stuck in an early boot-loop with error UEFI0256 after that.
You will not be able to downgrade the BIOS in that stage because the system resets before the Lifecycle Manager starts.
The only way to downgrade the BIOS is to temporarily remove the NVidia card, which of course means physical access to the system is needed.
View Reddit by OweH_OweH – View Source