I have some customer running ESXi installed on SD Card on HP Proliant servers Gen8 and Gen9, that has have problems where the ESXi could not write to the SD Card.
Some of them got this message i the vSphere Client.
Other has tried to update/upgrade hosts, and after reboot, it was still the same build.
All of them was running ILO 4 firmware 2.20, witch is distributed with HP SPP 2015.0.6.0, and there is a problem with this one, it look like it is fixed in version 2.22.
ILO 4 firmware 2.22 can be found here: http://h20564.www2.hpe.com/hpsc/swd/public/detail?sp4ts.oid=5264039&swItemId=MTX_30e9eb3e11104548a326deafbe&swEnvOid=4168
Update, 24th November 2016:
The recommended ILO 4 firmware is now 2.50