Patched OSInstaller.framework to allow macOS 10.13 installation on MBR partition.
To use those patched files you must create an USB installer. You can't just run the app downloaded from Mac App Store.
After creating the installer, copy the file like that:
OSInstaller to /System/Library/PrivateFrameworks/OSInstaller.framework/Versions/A
The patch is made base on 落下爱@pcbeta 10.10.x MBR patch method, and more patch for 10.13 Firmware check by crazybidy.
What is this patched OSInstaller doing?
1. Patch the MBR check, allow macOS 10.13 installation on MBR partition.
2. Patch the Firmware check, bypass the error of "An error occurred while verifying firmware".
3. This patched MBR OSInstaller method works with both MBR and GPT partition (GPT+recovery).
No longer need to set new SMbiosversion, FirmwareFeatures, and FirmwareFeaturesMask with this MBR-patch.
If you want to install to GPT, but still get the error of "An error occurred while verifying firmware".
All you need to do is, boot the Disk1mbrInstaller, and it will automatically load to install the "GPT-partition/macOS Install Data" which you installed with "Install macOS High Sierra.app" of createinstallmedia installer method at first stage.