You can flash all of them, I'm in the same boat, not new to HTC, but don't want to 100% void warranty. I have a vivid, just pick your Rom and kernel, then open the kernel and find boot.img then in fastboot type fastboot flash boot boot.img, then flash your Rom from recovery. Works well.
Sent from my HTC PH39100 using xda premium
[Current Phone] 2x Galaxy S4
[Phone Graveyard] HTC Evo->SGS 1 Epic->Samsung Infuse->
Atrix-> LG Thrill->Atrix 2->Inspire 4g->Focus Flash->HTC Vivid->
Captivate Glide (Wife).->HTC One X->Galaxy Note 2 & Galaxy S III (Wife)