Upgrade sequence PowerEdge servers

Hi Dell Community,

I would like to confirm if the following is the best and recommended sequence when upgrading firmware on PowerEdge servers (example: R740):

Based on my understanding, the safest upgrade order should be:

1. iDRAC

2. BIOS

3. CPLD

4. PERC RAID Controller

5. Other components (NIC, Backplane, Drives, PSU, etc.)

My reasoning is that updating iDRAC first ensures stability and compatibility for the rest of the upgrades. BIOS should come before CPLD since the CPLD firmware depends on the latest BIOS initialization. RAID controller firmware is updated afterward to avoid compatibility issues with older BIOS or CPLD versions.

Does Dell recommend this sequence as well?
And is it normal that the CPLD upgrade causes the iDRAC to go offline temporarily?

Thanks in advance for your guidance.