iLO firmware upgrade failed: iLO 4 not responding. System health monitoring has been disabled.

[MpDay]

Hi, I have an ML350 Gen8p and was using iLO 4 2.55. I started the upgrade to 2.70 using the regular .exe file from Windows Server. I've done about 90 upgrades already, never failed, but now during the upgrade I got a red cross telling me iLO wasn't responding. The FANs in the server were on maximum speed and wouldn't stop!

Rebooted the server and got this message:
iLO 4 not responding. System health monitoring has been disabled.

I've tried every recovery procedure I could find, but nothing works. I can PING to iLO, but that's all. I've tried:

- Power off, remove power cables for some minutes, power on: no change, same error.
- Press UID button for 10 seconds, which should reset iLO: no change.
- Start upgrade again from Windows Server: ERROR: Error fetching iLO security state.
- Start iLO management tool to reset iLO: cannot open: ERROR: Error fetching iLO security state.
- Start from SPP and to firmware upgrade from there: cannot find iLO (iLO not present in server).
- ftp to iLO works (user test, password flash), then I "put" the .bin firware but after a while I get an error: 
ftp> put c:\ilo4_270.bin
200 Ok.
425 cannot open data connection
ftp>

FANs are running at half speed constantly, our customer is going crazy because it's a lot of noise 24/7.
After using this guide, I can't find a solution: https://support.hpe.com/hpsc/doc/display?docId=emr_na-a00045315en_us&docLocale=en_US

How can we fix this please?

[Torsten.]

You could try this:

https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c02498232

Consider to use CP037959.scexe.

https://support.hpe.com/hpsc/swd/public/detail?swItemId=MTX_9e8cf11eecb74aa5b8b0f6331f