MSI B450 Gaming Pro Carbon AC - no POST after BIOS flashback

I don't think it's very fair to tar everyone with the same brush. Of course there will be a few people with serious PEBCAK issues but there's an obvious trend that can't be ignored. If vast swathes of people can't get their boards to post or flash properly then to me that doesn't imply a problem with the user. If, to use an example used above, using a smaller capacity thumb drive for the flashback works, then why the hell can't MSI put that information out in the ether? What I'm getting at is you can't call it a feature if the average user can't get it to work. And yes, that includes people who make a build twice a decade.
 
Current status is the PC struggles to POST. This morning it took about 15 resets to get it to boot. Once it's booted, it's fine and can be restarted no problem too. I've given up reflashing it now, tried it 5 times and it makes no difference. The flash is clearly working fine, the UEFI is just screwy.

The beta v18.1 UEFI seems to fix the boot issue for everyone that tried it on Reddit, but also seems to mess up idle voltages. Maybe that'll be fixed once v18.x is actually released.
 
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Well I got my mobo working (MSI B450M Mortar) originally it wouldn't post with the v18 BIOS tried multiple times, resetting RAM, CMOS etc etc.

Ended up trying to flash back to the v17 BIOS and since everything has been perfect, set my XMP profile to 3200mhz, have rebooted a lot of times, got Windows installed, done a bunch of updates, GPU drivers etc everything seems stable no crashes or failed posts and it boots up very quickly.

MSI Mortar B450M + Ryzen 5 3600X.
 
My B450 gaming pro carbon and 3700x combo wouldn't boot at all until I tried the bios link posted on Reddit. Everything else in the process stayed the same so user error was unlikely.
 
Hey guys, I have bought the b450 Gaming Pro Carbon Ac motherboard with Ryzen 5 3600 I have flashed the bios using the MSI.ROM downloaded from MSI blog page I have a new SSD with brand new windows OS installed on it and 2x 8GB DDR4 HyperX RAM After I flashed the Bios I assembled everything and tried to powered it on but the PC keeps shutting down and restarting while posting all kinds of error messages. Sometimes it won't boot, sometimes it crashes during the MSI logo and sometimes I get even to typing my password into Windows and it shuts there I am rly desperate now cuz I tried many things and nothing works it is doing the same things.
 
Current status is the PC struggles to POST. This morning it took about 15 resets to get it to boot. Once it's booted, it's fine and can be restarted no problem too. I've given up reflashing it now, tried it 5 times and it makes no difference. The flash is clearly working fine, the UEFI is just screwy.

The beta v18.1 UEFI seems to fix the boot issue for everyone that tried it on Reddit, but also seems to mess up idle voltages. Maybe that'll be fixed once v18.x is actually released.
New BIOS version 7B85v18 for the B450 Gaming Pro Carbon AC released on official support page.
https://www.msi.com/Motherboard/support/B450-GAMING-PRO-CARBON-AC
 
Can anyone give a step by step guide to doing this in detail? I've watched videos, read forums, done everything i can possibly find to the point. The board acts as if the updates go through fine. The difference i have from a lot of you is i only have a 3400g installed. I did try to hook a 1050ti just to see but still zero post screen. The board powers on led's and all that, seems to flashback, refuses to show anything on screen. I have two ddr4 3000 8gb ram sticks, I've tried just one, still nothing. I've tried the v16 v17 and v18, even the new beta build v193.
 
Can anyone give a step by step guide to doing this in detail? I've watched videos, read forums, done everything i can possibly find to the point. The board acts as if the updates go through fine. The difference i have from a lot of you is i only have a 3400g installed. I did try to hook a 1050ti just to see but still zero post screen. The board powers on led's and all that, seems to flashback, refuses to show anything on screen. I have two ddr4 3000 8gb ram sticks, I've tried just one, still nothing. I've tried the v16 v17 and v18, even the new beta build v193.
Assuming you have the MSI B450 Gaming Pro Carbon AC, the BIOS downloads can be found here:
https://www.msi.com/Motherboard/support/B450-GAMING-PRO-CARBON-AC

Try the following:
  1. Unplug/remove the 24pin power cable, CPU power cable(s), CPU, RAM, GPU, PCIe devices, M.2 devices, SATA devices, USB devices from the motherboard.
  2. Remove the CMOS battery from the motherboard for about 5 minutes. After 5 minutes, reinstall only the CMOS battery and reconnect the 24pin power cable and CPU power cable (8pin EPS cable). Leave the remaining components disconnected.
  3. Get a USB flash drive of 16GB capacity or less. Make sure your USB flash drive is formatted to FAT32. To make sure your USB Flash Drive is formatted correctly, you can use a third party program such as RUFUS.
  4. Make sure to extract the contents of the downloaded 7B85v193.zip file, and rename the extracted file from E7B85AMS.193 (it may be inside sub-folders) to MSI.ROM
  5. Place the MSI.ROM file in the root directory of your FAT32 formatted USB flash drive.
  6. Make sure you connect the USB flash drive to the correct Flashback USB port on the motherboard. Then press the Flashback button.
  7. Wait about 5-6 minutes for the flashing process to finish and the Flashback LED to stop blinking.
  8. Once the Flashback LED has stopped blinking and everything looks idle, then turn off power from PSU and remove the USB flash drive.
  9. Reinstall only the CPU and RAM (A2/B2 DIMM slots). The 8pin EPS and 24pin motherboard power cables still need to be connected.
  10. Connect keyboard and display output cable from motherboard to monitor (not TV as they can sometimes cause issues).
  11. Try to boot up by using a screwdriver to briefly bridge the power switch pins on the front panel header of the motherboard. First boot up might take a couple on minutes and may restart a few times automatically.
Video guide by MSI:
 
Well after following your directions closely I've sat here with the first boot for about 5 minutes and nothing. I was using hdmi now I'm trying display port. Still no output. I don't even have a debug light on anything.
 
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