Fastboot permission denied error in Asus Zenfone 2
Ok i was able to fix the problem. I was still able to load TWRP by flashboot, which I used to fix permissions and clear cache. The problem started because I went into normal recovery and went to wipe cache partition to load the SuperZen rom. The cache wipe seemed to take long, so I turned the phone off and back on and the only thing I was able to load was the fast boot. No recovery or normal mode worked, just ended up with a dead android. After fixing cache partition, I reloaded same 3 img files, kept getting permission denied error. Tried to get into recovery again and this time it worked! I used ADB sideload to flash the zip file above and it worked!