[coreboot] Max RAM problem

[Ale]

Hello everyone,
I have a kgpe d16 motherboard with coreboot and seabios, and 2 opteron 6282 SE processor with 64 gb of RAM: all the modules are 16 Gb hynix HMT42GR7AFR4C - RD and all are inserted into the orange slots. The problem is, if I add 2 additional modules, inside the last 2 orange slots, the machine doesn't starts and only black screen is shown, no log is detected over COM port. Any suggestion? Maybe another RAM module configuration is needed, because I read that 192 Gb of RAM is possible to obtain (I have followed the official Asus manual for the RAM-Slots configuration)

Thank you very much
Best regards
Ale