[HTC EVO 3D] thos25:
I apologize in advance for being lengthy, but I want to be thorough to give you a good idea of what I did. Hopefully someone will point out what I did right or wrong.

I had this same exact problem with MIUI the other day. I am not an expert on rooting/flashing, but I was able to resolve the issue with a little trial and error.

I flashed MIUI on my 3d. I wasnt too impressed with it really and flashed back to Eternity. A few days passed and I decided to give MIUI another shot and flashed back a second time. Mind you, I always do a factory reset twice, wipe cache twice, and wipe dalvik cache twice before any flash (even if it is an updated version of the ROM I am using), so I made sure to wipe everything before flashing. When I flashed I noticed the little bug on the notification bar area of MIUI and thought it was a clever way of showing debug mode was on.

After messing with it some more I realized that I just plain didnt like it and giving it any more time was not neccessary. I decided to flash back to Eternity. I booted up my phone into bootloader and tried to get into fastboot USB, but it wouldnt activate when I put my USB in. I rebooted into MIUI to make sure I didn't mistakenly turn debugging off. It was still on. I tried to get into fastboot USB a second time. Still an error. I searched XDA came across this thread. Noted that USB debug was on. Followed steps, no progress.

At this point I figured I would just try to flash eternity to see what happened without using fastboot. Froze on bootup. So I flashed MIUI back on. I then remembered hearing about Flash Image GUI on market (made by JoeyKrim who posted above me in this thread). I figured I would give it a shot.

Failed. I had Ziggy kernel from Eternity already on my SD, so I flashed that. It said it was successful. So I powered down. Then I booted into bootloader and went into recovery. I tried to flash Eternity and it froze during boot. I tried to boot up several times and always froze. I went back to MIUI figuring that perhaps the kernel really didnt flash. MIUI made it past boot, to the lockscreen, but I couldnt unlock it. Bascially I was stuck. None of the buttons worked except for power. I tried again to reboot MIUI again. Same problem.

Starting to get a bit desperate, and not being able to get into fastboot USB at all, I figured I could try to nand restore to stock rooted. Of course...still wont work since I couldnt access fastboot USB. My screen froze during boot on this as well.

So here I am stuck with no fastboot USB, a restore that wont flash, Eternity wont flash, and MIUI isnt responding. Honestly I was getting upset and had half a mind to hit the phone with a stun gun and take it to Sprint. (not my idea, but a Sprint person told me once to fry it and take it in and they would say it was a battery short which fried it). Anyhow. I then figured I would try RUU. Problem was that I heard RUU wont work unless you are locked. So I tried to re-lock, and of course couldnt do it since fastboto USB wont work.

I decided to hit the RUU anyhow and it failed saying it was Security fail. I wazs thinking of options, hit it with stun gun hopefully sprint replaced, sink it and insurance replace it, or just head to sprint to see if they could help. But much to my surprise, I tried to boot into bootloader one more time and sure enough fastboot USB was back. My recovery was gone, so I flashed CWM again and was able to put eternity back on. The only problem is that my CWM was deleted and I lost my Nand. Not too big a deal as I can always put a stock rooted rom on and use that as my Nand. Or I can always just RUU to stock, then re-root just to be certain I have a clean nand.

Alright guys. Anyone care to comment on what could have been done differently?