Added Apple Silicon instructions

Necessary to support the new Apple Silicon (M1) chips and older
Intel-based systems.

README.adoc

@@ -126,7 +126,7 @@ macOS Boot Disk Tips
 macOS Boot Disk Usage:
   1. Insert the USB boot disk into the machine to be upgraded.
   2. Reboot the machine.
-  3. Hold down the OPTION key before the Apple logo appears.
+  3. Hold the POWER (Silicon) or OPTION (Intel) key before the Apple logo appears.
   4. Select the USB boot disk from the menu.
   5. Use Disk Utility to delete and/or erase the hard drive including associated partitions.
   6. Use Disk Utility to create a single "APFS" drive as a "GUID Partition Table".
@@ -134,7 +134,7 @@ macOS Boot Disk Usage:
 
 macOS Boot Disk Recovery:
   1. Start/restart the machine.
-  2. Hold down the COMMAND+R keys before the Apple logo appears.
+  2. Hold the POWER (Silicon) or COMMAND+R (Intel) keys before the Apple logo appears.
   3. Wait for the macOS installer to load from the recovery partition.
   4. Use the dialog options to launch Disk Utility, reinstall the system, etc.
 ....
@@ -172,16 +172,16 @@ link:https://www.alchemists.io/projects/mac_os-config[macOS Config] project for
   upgrading as you might experience various errors with Apple not being able to detect an internet
   connection which prevents the installer from working.
 * When using the boot disk and the installer fails in some catestrophic manner, reboot the machine
-  into recovery mode (i.e. `COMMAND + R`) to download and install the last operating system used.
-  Alternatively, you can also use `COMMAND + OPTION + R` to attemp to download the latest operating
-  system.
+  into recovery mode -- `POWER` (Silicon) or `COMMAND + R` (Intel) buttons -- to download and
+  install the last operating system used. Alternatively, you can also use `COMMAND + OPTION + R`
+  (Intel) to attemp to download the latest operating system.
 * When using the boot disk, you might experience a situation where you see a black screen with a
   white circle and diagonal line running through it. This means macOS lost or can’t find the boot
   disk for some reason. To correct this, shut down and boot up the system again while holding down
-  the `OPTION+COMMAND+R+P` keys simultaneously. You might want to wait for the system boot sound to
-  happen a few times before releasing the keys. This will clear the system NVRAM/PRAM. At this point
-  you can shut down and restart the system following the boot disk instructions (the boot disk will
-  be recognized now).
+  the `OPTION + COMMAND + R + P` (Intel) keys simultaneously. You might want to wait for the system
+  boot sound to happen a few times before releasing the keys. This will clear the system NVRAM/PRAM.
+  At this point you can shut down and restart the system following the boot disk instructions (the
+  boot disk will be recognized now).
 
 == Development
 

bin/create_boot_disk

@@ -9,14 +9,14 @@ printf "  - Use Disk Utility to label the USB drive as \"Untitled\".\n"
 printf "\nmacOS Boot Disk Usage:\n"
 printf "  1. Insert the USB boot disk into the machine to be upgraded.\n"
 printf "  2. Reboot the machine.\n"
-printf "  3. Hold down the OPTION key before the Apple logo appears.\n"
+printf "  3. Hold the POWER (Silicon) or OPTION (Intel) key before the Apple logo appears.\n"
 printf "  4. Select the USB boot disk from the menu.\n"
 printf "  5. Use Disk Utility to delete and/or erase the hard drive including associated partitions.\n"
 printf "  6. Use Disk Utility to create a single \"APFS\" drive as a \"GUID Partition Table\".\n"
 printf "  7. Install the new operating system.\n"
 printf "\nmacOS Boot Disk Recovery:\n"
 printf "  1. Start/restart the machine.\n"
-printf "  2. Hold down the COMMAND+R keys before the Apple logo appears.\n"
+printf "  2. Hold the POWER (Silicon) or COMMAND+R (Intel) keys before the Apple logo appears.\n"
 printf "  3. Wait for the macOS installer to load from the recovery partition.\n"
 printf "  4. Use the dialog options to launch Disk Utility, reinstall the system, etc.\n"