diff --git a/lib/scripts/isabelle-platform b/lib/scripts/isabelle-platform
--- a/lib/scripts/isabelle-platform
+++ b/lib/scripts/isabelle-platform
@@ -1,61 +1,61 @@
 # -*- shell-script -*- :mode=shellscript:
 #
 # determine general hardware and operating system type for Isabelle system tools
 #
 
 ISABELLE_PLATFORM_FAMILY=""
 ISABELLE_PLATFORM32=""
 ISABELLE_PLATFORM64=""
 ISABELLE_APPLE_PLATFORM64=""
 ISABELLE_WINDOWS_PLATFORM32=""
 ISABELLE_WINDOWS_PLATFORM64=""
 
 case $(uname -s) in
   Linux)
     ISABELLE_PLATFORM_FAMILY="linux"
     case $(uname -m) in
       aarch64)
         ISABELLE_PLATFORM64=arm64-linux
         ;;
       arm*)
         ISABELLE_PLATFORM32=arm32-linux
         ;;
       *)
         ISABELLE_PLATFORM32=x86-linux
         ISABELLE_PLATFORM64=x86_64-linux
         ;;
     esac
     ;;
   Darwin)
     ISABELLE_PLATFORM_FAMILY="macos"
     case $(sw_vers -productVersion) in
       10.10*|10.11*|10.12*|10.13*|10.14*)
         ISABELLE_PLATFORM32=x86-darwin
         ISABELLE_PLATFORM64=x86_64-darwin
         ;;
       *)
         ISABELLE_PLATFORM64=x86_64-darwin
-        case $(uname -m) in
-          arm64)
+        case $(uname -a) in
+          *arm64*|*ARM64*)
             ISABELLE_APPLE_PLATFORM64=arm64-darwin
             ;;
           *)
             ;;
         esac
         ;;
     esac
     ;;
   CYGWIN_NT*)
     ISABELLE_PLATFORM_FAMILY="windows"
     ISABELLE_WINDOWS_PLATFORM32="x86-windows"
     ISABELLE_WINDOWS_PLATFORM64="x86_64-windows"
     case $(uname -m) in
       x86_64)
         ISABELLE_PLATFORM64=x86_64-cygwin
         ;;
       i?86)
         ISABELLE_PLATFORM32=x86-cygwin
         ;;
     esac
     ;;
 esac