Well I flashed my Z87 with IMEI 9.1 for Broadwell (@ Asus site, found by Z97 mobos), it worked but it made bugged blck clock for my 4770K,..
It got pinned to 100.96MHz and windows saw it as 101MHz, also sometimes it would bsod by windows logon (bsod 0x124) since it now raised cpu freq. a bit, e.g. 4.6GHz >>> 4.64GHz.
This clock bug appeared as soon as I enabled XMP, with it off it would function normally and set it to 100MHz.
Also first time when I flashed this IMEI I got some strange prompt about tunderbolt and not enough UEFI memory or something.. It went away after another hardreset/restore UEFI to default..
So I guess if I had Broadwell cpu and used that IMEI it should theoretically work, maybe this IMEI is really only Broadwell blck specific.
btw PCH diagram is the same for both Z87 & Z97, that's why intel ceo said that what he said, but now I see its mostly for marketing and why they left old system out, but then again slight delay would make more sense, not left it out entirely..
*corp
But careful with this IMEI firmware update, I almost thought I bricked my mobo bios, couldn't flash back to old 9.0, after some 2-3hr panic I finally tested Asus flashback and that worked as intended. Got a bit lucky my mobo didn't have write protected IMEI fw.