My upgrade was from U2d though - and the original u2 image was a Dell customized image. Booted from that ISO to do in-place upgrade from earlier 6.7 and then 7.0 - and I had to go through some VIB removals then.
Also using TPM and secure boot on them now. The annoying thing is no log or error message tells you it's VIB's when using remediation or esxcli install. No sure if you tried yet -but get the U3 full .iso - boot from it (iDrac etc) - if there are more vib's - that install/upgrade from ISO will tell you which ones. (yes a long process)