If you attempted a firmware upgrade with iDRAC 7 or 8 and fail with the following error :
RED007: Unable to verify Update Package signature.
First, make sure the file isn’t corrupted by checking md5sum from the Web site and the downloaded file. If the signature align, there is a very good chance that your current running iDRAC firmware version is very old (before version 2.40.40.40).
The failure occur because Dell dropped SHA-1 signatures on newer version and the firmware released after that iDRAC firmware version cannot be validated du to that change.
Since the server candidate I had the opportunity to work on for this case was not updated since it was installed almost a decade ago, therefore was seriously lagging behind versions.
Upating to latest version would fail due to the very same issue. A step upgrade will be required, in my case it looked like the following :
Pre 2.40.x.x_xx version -> 2.40.40.40_A00 -> 2.63.60.61_A00 -> 2.70.70.70_A00 -> 2.84.84.84_A00 […]
Once iDRAC will be up to date to a recent version, updates from iDRAC for other firmwares will work normally.