Add troubleshooting steps for missing EFI.

docs/TROUBLESHOOTING.md

@@ -8,6 +8,7 @@ Here are some common errors that users may experience while using this patcher:
 * [Stuck on hard disk selection with greyed out buttons in installer](#stuck-on-hard-disk-selection-with-greyed-out-buttons-in-installer)
 * [Cannot boot macOS without the USB](#cannot-boot-macos-without-the-usb)
 * [Infinite Recovery OS Booting](#infinite-recovery-os-reboot)
+* [Internal EFI missing when building OpenCore](#internal-efi-missing-when-building-opencore)
 * [System version mismatch error when root patching](#system-version-mismatch-error-when-root-patching)
 * [Stuck on boot after root patching](#stuck-on-boot-after-root-patching)
 * ["Unable to resolve dependencies, error code 71" when root patching](#unable-to-resolve-dependencies-error-code-71-when-root-patching)
@@ -86,6 +87,25 @@ With OpenCore Legacy Patcher, we rely on Apple Secure Boot to ensure OS updates
 
 * Note: Machines with modified root volumes will also result in an infinite recovery loop until integrity is restored.
 
+## Internal EFI missing when building OpenCore
+
+If you're using a brand new disk that has not been used before or was never formatted in any macOS type, you may face the following error in OCLP when trying to build on the internal disk.
+
+<div align="left">
+             <img src="./images/OCLP_Failed_to_find_applicable_disks.png" alt="Failed to find applicable disks" width="800" />
+</div>
+
+There are two ways to to try and resolve this.
+
+1. Create a new FAT32 partition using Disk Utility, sized at around 100MB, naming does not matter. OpenCore will detect it and you will be able to build your EFI there.
+
+2. When installing macOS, choose "View -> Show all devices" in Disk Utility and format the entire disk by choosing the topmost option in the sidebar.
+
+<div align="left">
+             <img src="./images/wipe-disk.png" alt="Wipe disk" width="800" />
+</div>
+
+
 ## System version mismatch error when root patching
 
 Updates from now on modify the system volume already while downloading, which can lead to broken patches out of a sudden as well as a "version mismatch" error while root patching, since the operating system gets into a liminal state between two versions. The "version mismatch" error is a safeguard preventing OCLP from patching on a system that is in a weird liminal state, to avoid leading to a very likely boot failure.