ASROCK and MSI z370 MB with i3-8100 and i3-8350k not booting

Mar 9, 2018
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recently purchased ASROCK z370 mobo and i3-8100 both working. Decided to upgrade cpu to i3-8350k. 8350k installed, failed to boot, returned 8100 to asRock mobo and 8100 failed to boot. RMA'd the asRock, Purchased MSI z370 a pro mobo, tried same cpu's again, failed to boot.
While the bios may be an issue, how do you update a bios when a mobo won't boot in the first place? Are there bios problems with the MSI and AsRock and the new i3 8th generation cpus? My next thought was to try an a ASUS board, but I am concerned it will fail also.
Been through all the steps for building a PC from this website, and I have built others in the past without non-booting issues.