One thing to check, make sure the 8-pin cpu power cable is fully seated and clicked into place.

If it still doesn't want to go, it's looking like a motherboard or cpu problem.

Do you have another set of memory to test?

It sounds like the bios might have become corrupted after the first flash.

You're best option would be an RMA through Amazon if you're within the return period.

Good luck!

Alright I'll return it. Here's the CPU pins just beforeI put the cover on in case Asus gives Amazon trouble who then give me trouble. Paper trail and all of that.

As Nate152 had mentioned...it's very possible that the bios became corrupted during the flash....use the bios flashback method and rename the file.....I would also suggest to remove cmos battery to clear close....As well....I have seen instances where the memory has been the culprit ...what model # Corsair memory are you using ???....also try the reset switch on board.....error code 00 means that your CPU is not being recognized for some reason....doubt that it is the CPU...atm (since it looks like the board booted fine with bios that initially came with board)..but more likely a fault with the board (bios chip) in the end after the bios update.... if the the above suggestion fails to rectify you issue.
Test the board outside the case....looks like you have it already out anyway for an RMA....nothing to lose.

@CULBRELAI
Just under the q-code read out there are i believe 4 tiny surface mounted devices [SMD] LEDs, the one on the far left when facing the q-code read out is an orange LED with "CPU" typed next to it. If that LED is lit orange with q-code 00 it is very likely your CPU is faulty.

This is what happened to me with my Maximus X Hero a few weeks ago. I do not know if it was coincidental, but a day after I update to the latest BIOS 1602, and tried to reboot my system because I found it non-responsive in the morning, after the reboot I got the 00 q-code and orange CPU light was lit just under the q-code. That CPU was an i7 8700k. I put in a brand new i7 8086K and it booted up fine, so I got the i7 8700K replaced for a new one.

My suggestion is to check if the orange CPU LED is lit with q-code 00. I will try to demonstrate with text to show where this LED is found under the q-code read out:

[0][0]
. . . .

In the above the CPU LED is the "." on the far left under the [0][0] q-code with the letters "CPU" written next to the SMD LED.

I'm having this exact qcode issue after trying to update my BIOS. Everything updated normally, said 100% successful, upon rebooting I got code 00 and CPU LED stays lit. I get no video out at all.

I bought a cheap H310 motherboard to test if my 8700k is faulty and it's not, my 8700k boots perfectly in that board. So it has to be the M10HWIFI motherboard. I've been trying to flashback the BIOS to any BIOS file on the Asus site and nothing is working. Has anyone found a fix or am I just going to need to RMA the board again?

I know this is about Maxiums X Z370 but I just wanted to share what just happened to my other older machine with a Maximus VIII Ranger with an i7 7700k. Last 2 weeks or so it put out an error beep of 1 long and 4 short beeps twice a few days apart, but the machine booted up to Windows and ran fine.

Tonight I went to start it and I got the bleeding Q-Code 00 with CPU fan running at full speed. Not able to go any further than that. Apparently 1 long beep with 4 short beeps means "Failure of Hardware component" so I swapped the RAM with my new Maximus X Hero's RAM [from this machine], no go. Took out the ASUS GTX1060 and tried the iGPU, no go. Took out the CPU and I noticed that there was some sort of corrosion on some of the golden connectors, but a wipe with a alcohol swab cleaned it right up. Reseated it put new heatsink compound and then put on the Noctua air cooler, still no go.

In the morning I'm going to have to go through this thing more deeper and hopefully work out what the problems is. Otherwise I got a brand new i7 8700k that was replaced a few weeks ago [see my previous post] so I might have to upgrade this motherboard for a Z370. However, in all the years that I've built PC's this is the first time that I have blown a CPU a few weeks back a day after updating the BIOS to 1602 of this Maximus X Hero and now this... i am wondering if I should try something other than ASUS, which I've been using exclusively since 2002. This can not simply be coincidence... but poor quality control if you ask me.

UPDATE: First I must apologize for applying that this looked like an ASUS fault due to poor quality control. To cut a long story short, the problem ended up being the Display Port cable. After changing the connection to the montor from the GTX1060 from DP to HDMI, the machine passed the q-code 00, got the very welcomed single beep and after passing POST windows loaded and has been running fine all day and night.

I've still got a bit of work to do, because my curious mind want to know if it's actually the DP cable, or the monitor/VGA card DP circuitry, but I doubt that it is the latter two.

I feel so relieved and happy that I do not have to do what I was afraid I had to do.... pheeeew!!!