[ArtOfCombat]

I need help statting... a cyberzombie great dragon. I am giving my players the tools to defeat it, but I don't even know where to start. Any ideas?

[Prime Mover]

No easy way in current edition.  Could use 4th edition rules and crowbar cyber zombie rules onto template.  Could always go Shedim route and do possessed zombie dragon. Lots of lesser shedim minions, could be an interesting last stand situation.

[Michael Chandra]

No easy way in current edition.  Could use 4th edition rules and crowbar cyber zombie rules onto template.  Could always go Shedim route and do possessed zombie dragon. Lots of lesser shedim minions, could be an interesting last stand situation.

Chicago players will have tips on dealing with a Bug Queen Dragon.

[Finstersang]

O boi, what did your players do to you 

My main Tipp: Don´t overthink it. You´re the gamemaster, nobody will see the stats and logic behind your creation. Since you already provide the Silver Bullet to bring him down, you will probably already aim for a mostly narrative approach. There´s no rules for Cyberzombies in 5E anyways.

Suggested Adaptations:

• Remove/freeze the Dragon´s Magic Abilities. If you don´t want to throw it out completely, cut the Magic down to player level and let him/her have just some distinct, impactfull manipulations spells, just enough for the players to be afraid that this thing can still cast them. The fokus should be on the Augmentations, though.
• About Dragonspeach ("Mind-Talk"): Your Decision. Maybe he/she goes mute. What would also be cool if the Dragon lets out constant tortured "mind wails" in the near vicinity. Use that as flavour or even add a Modifier for the distraction.
• About Elemental Attack ("The Breath"): Will also be hampered by the Augmentations, maybe he/she even loses it. Consider replacing the Breath by a Jaw-Mounted Heavy Cyberweapon. Looks terrifying, and it´s plausible if the Dragon can use it with the Exotic Weapon Skill that´s usually for the Breath.
• Add a negative Background Count for Magic (using whatever ruling you prefer). It´s canon that Cyberzombies are a blight in Astral Space.
• Most standard and protective Augmentations (Bone Lacing, Muscle Replacements etc.) don´t really change the dragons high Attributes and Armor in a meaningfull way, so don´t bother with adjusting them and just describe the cybered body of the creature.
• For the Augmentations that actually matter, consider futuristic Gizmos, additional weapons and experimental stuff and don´t let yourself be constricted to the official wares in the rulebook. Suggestions: The Jaw-Gun mentioned above, Signal Jammers and EMP, Sensor Suite for detecting hostiles, Adaptive Camouflage Scales, Smoke Projectors, Defensive Laser Arrays (to shoot down missiles), High-Powered Speakers for Sonic Blast Attacks, Regenerative Bioware...
• If you have a Hacker, give him/her something to do. Maybe some of the Augmentations run wirelessly because whoever built that thing is tracking/monitoring it?