You need to use a Dell Update Package from either the iDRAC web interface or the operating system. If the backflash still fails then it is not permitted. The backflash will not be permitted if conditions are met that would cause the system to not be able to complete POST after the backflash. The conditions are listed on the 1.4.5 download page. No backflash method will work if those conditions are met.
Hello, I am trying to down rev an R640 BIOS from 1.6.12 to 1.3.7. The BIOS was initially 1.6.11 and I was able to update to 1.6.12 but I can not down rev to 1.3.7 from 1.6.11 or 1.6.12. The issue is only seen on one R640 as I can down rev other R640s. The down rev BIOS is staged fine but does not update correctly after a reboot. I have tried a power drain and racadm systemerase commands to no success. This is what the LC Log says for the failed BIOS update.
can not down rev R640 BIOS