BIOS upgrade on R720 from 1.6.0 to 2.9.0 - Windows Server 2008 R2

There are a few version of bios between 1.6 and 2.9, but the more important item to update is the idrac. 
What version is your idrac?
#Iwork4Dell

Hello @DELL-Rey G ,

Thank you for your reply, much appreciated.

The iDRAC version is 1.35.35 (build 7) It is iDRAC7.

I cannot access it because someone has given it the same IP address as the actual server! Not sure even if it is connected at the moment.

Why is it more important to update the iDRAC?

Thank you.

If the idrac is too old, none of the other updates will be allowed to run. In addition, if I recall correctly, idrac 1.57.57 resolves the error message you are seeing. I cant confirm, but I think thats right. The important thing here is to step the idrac upgrades. if you make too big of a version jump it can cause problems. It will take longer, but I would step your way up from the 1.46.45 to 2.52.52.52, then it should be safe to go to 2.63.60.62 from there. Because of the current version of idrac, you will need to use a specific method to update the idrac. From the support site at this this link, https://www.dell.com/support/home/us/en/04/drivers/driversdetails?driverid=3f4wv&oscode=ws8r2&productcode=poweredge-r720
download the iDRAC7__1.66.65__A00.exe file, and run it to extract the firmimg.d7 file. In the idrac webpage left pane, under Server, go to logs and clear the sel log, then go to iDrac settings, Update and rollback, and point the firmware update to the location of the .d7 file you extracted. continue the process of updating the iDrac. Once the update is totally complete, I would suggest gracefully powering down the system if its powered on, then removing power cords from the system for about 15 seconds. This last step isnt documented anywhere, but in my experience it allows the idrac to boot up with its "cache" empty and it spins up the new fw version in a "clean" memory state. Then continue this process with the other idrac versions. At about v2.52.52.52, you could proceed with the bios update and shouldnt have any problems. Each version of idrac will have a similar style file
name that has the firmimg.d7 file to extract. 

#Iwork4Dell

Hi,

It is recommended to update the iDRAC and Lifecycle first before updating the BIOS. To answer your question, yes you still need to update the iDRAC firmware then only updating the BIOS. 

Let me know if you have any other questions.

If I don,t use iDrac, I directly go to life cycle controller and update bios firmware and is it still need the upgrade iDrac version?