Hello. When several revisions behind, iDRAC and BIOS are updated concurrently step-wise up to current version with BIOS applied first then iDRAC. You might consider replacing then board if draining the system flea has not resolved the communication failure.
Hi. I seem to have scrapped 2x PE R720s by "upgrading" idrac7  from 1.35.35 to 2.30.30. Unfortunately both R720s are no longer under waranty. any fix? idrac7 communication error now. blank lcd screen....etc. I've tried the power drain already.
urgent: jump from idrac7 1.35.35 to 2.30.30 causing idrac7 to fault