Booting into the prohibited symbol
- Thread starter momchilh
- Start date
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Hello Guest. Before you post check the Troubleshooting guide here, Dortania Troubleshooting
Booting in to a prohibited symbol usually means the USB port you are using for the installer has been dropped as part of the switch from Bios control, to OpenCore control and finally to the macOS installer control.
Often a USB port that happily boots the OpenCore EFI and installer will be dropped by macOS, due to USB configuration issues in the OpenCore setup being used. An incorrectly configured UTBMap.kext or USBMap.kext or the total lack of a custom USB configuration is the normal culprit for this issue.
Looking through your EFI's Kext folder it is clear that you lack a custom UTBMap.kext to pair with USBToolBox.kext. The later kext does nothing on its own. You need to run the USBToolBox Tool in Windows, discover the system USB ports and generate a custom UTBMap.kext for your system to have working USB ports.
If the system lacks a custom USB configuration then this more often than not leads to USB port failure during the installation phase.
I assume this is your initial installation of maCOS on this B850M system. That being the case I would recommend you try running an earlier version of maCOS, Ventura, Sonoma or Sequoia would all work better than Tahoe as a first time installation.
Your EFI isn't configured for the installation of macOS on any B850 motherboard, To be honest I don't think it would work on any AMD Hack.
You need to do some more research and read through the guides over at Dortania's OpenCore site.
Your alternative is to look to see if anyone else has managed to install macOS on the same or a similar 800 series AMD board as you are using and use their EFI as a base.
Often a USB port that happily boots the OpenCore EFI and installer will be dropped by macOS, due to USB configuration issues in the OpenCore setup being used. An incorrectly configured UTBMap.kext or USBMap.kext or the total lack of a custom USB configuration is the normal culprit for this issue.
Looking through your EFI's Kext folder it is clear that you lack a custom UTBMap.kext to pair with USBToolBox.kext. The later kext does nothing on its own. You need to run the USBToolBox Tool in Windows, discover the system USB ports and generate a custom UTBMap.kext for your system to have working USB ports.
If the system lacks a custom USB configuration then this more often than not leads to USB port failure during the installation phase.
I assume this is your initial installation of maCOS on this B850M system. That being the case I would recommend you try running an earlier version of maCOS, Ventura, Sonoma or Sequoia would all work better than Tahoe as a first time installation.
Your EFI isn't configured for the installation of macOS on any B850 motherboard, To be honest I don't think it would work on any AMD Hack.
You need to do some more research and read through the guides over at Dortania's OpenCore site.
Your alternative is to look to see if anyone else has managed to install macOS on the same or a similar 800 series AMD board as you are using and use their EFI as a base.
Thanks a ton, not sure how i missed to add the USBMap.kext. Also, what do you mean by my EFI isn't configured correctly for the Motherboard? Just hint me in a direction and i'll look into it. Thanks again!
Off the top of my head your setup is missing the following elements:
I would recommend you look at another 800-series setup for a more complete idea of what is required. Below are a couple of links to success stories for 800-series systems, which might help.
- ACPI patches, which are required for AM5 systems.
- The config.plist doesn’t have any MmioWhitelist entries.
- The AM5 Kernel patch (No. 18) in your config.plist is not enabled.
I would recommend you look at another 800-series setup for a more complete idea of what is required. Below are a couple of links to success stories for 800-series systems, which might help.
UPDATED ON 3 MARCH 2026
MY SECOND AMD HACKINTOSH
and its working perfectly - big thanks to this awesome community
MAINBOARD
ASUS ROG Crosshair X870E Extreme (BIOS 1715)
ROG-X870E-X
Realtek SupremeFX USB Audio (ALC4082) √
Realtek 5Gbit Network Adapter (RTL8126A) √
Aquantia/Marvell FastLinQ Edge 10Gbit Network Adapter (AQC113CS) √
MediaTek Wi-Fi 7 BT5.3 (MT7927) X (not supported in macOS) (removed from mainboard)
ASMedia USB4 (ASM4242) X (not...
MY SECOND AMD HACKINTOSH
and its working perfectly - big thanks to this awesome community
MAINBOARD
ASUS ROG Crosshair X870E Extreme (BIOS 1715)
ROG-X870E-X
Realtek SupremeFX USB Audio (ALC4082) √
Realtek 5Gbit Network Adapter (RTL8126A) √
Aquantia/Marvell FastLinQ Edge 10Gbit Network Adapter (AQC113CS) √
MediaTek Wi-Fi 7 BT5.3 (MT7927) X (not supported in macOS) (removed from mainboard)
ASMedia USB4 (ASM4242) X (not...
Okay so i guess progress has been made. I generated the ACPI patches my system needs: SSDT-EC.aml; SSDT-PLUG-ALT.aml and SSDT-USBX.aml. I checked whether i need SSDT-AWAC/RTC0, but the SSDTTime tool said there are no devices to patch. About MmioWhitelist, i dont understand what entries i need to have in my efi configuration (probably to map the USB ill be booting from?), the Dortania guide only has information about it for the TRx40 models. Since thats not my case, i dont see what i have to add here. Or do i? I read on reddit that it may be useful to play around with the DevirtualiseMmio quirk and match it with something? The cases you sent me are with motherboards from the same 800-series, yes, but i still dont know if i should follow the dortania guide that mainly targets machines with "TRx40"s, since i can see that the link leads me to a fix in kaslr. BTW the log is from my latest configuration, just attaching it in case somebody needs it in the future.
You need to boot with the OpenCore Debug version and follow the guidelines in the link below. So you can extract the MmioWhitelist entries for your system. It doesn’t matter if your system doesn’t boot to macOS, as the settings to generate the MmioWhitelist entries will be in the OC log that is generated by the Debug EFI.