diff --git a/lib/scripts/isabelle-platform b/lib/scripts/isabelle-platform
--- a/lib/scripts/isabelle-platform
+++ b/lib/scripts/isabelle-platform
@@ -1,50 +1,53 @@
 # -*- shell-script -*- :mode=shellscript:
 #
 # determine general hardware and operating system type for Isabelle system tools
 #
 
 ISABELLE_PLATFORM_FAMILY=""
 ISABELLE_PLATFORM32=""
 ISABELLE_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
         ;;
     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
diff --git a/src/Pure/System/platform.scala b/src/Pure/System/platform.scala
--- a/src/Pure/System/platform.scala
+++ b/src/Pure/System/platform.scala
@@ -1,73 +1,75 @@
 /*  Title:      Pure/System/platform.scala
     Author:     Makarius
 
 System platform identification.
 */
 
 package isabelle
 
 
 object Platform
 {
   /* platform family */
 
   val is_linux: Boolean = System.getProperty("os.name", "") == "Linux"
   val is_macos: Boolean = System.getProperty("os.name", "") == "Mac OS X"
   val is_windows: Boolean = System.getProperty("os.name", "").startsWith("Windows")
 
   def family: Family.Value =
     if (is_linux) Family.linux
     else if (is_macos) Family.macos
     else if (is_windows) Family.windows
     else error("Failed to determine current platform family")
 
   object Family extends Enumeration
   {
     val linux, macos, windows = Value
 
     def unapply(name: String): Option[Value] =
       try { Some(withName(name)) }
       catch { case _: NoSuchElementException => None }
 
     def parse(name: String): Value =
       unapply(name) getOrElse error("Bad platform family: " + quote(name))
   }
 
 
   /* platform identifiers */
 
   private val X86 = """i.86|x86""".r
   private val X86_64 = """amd64|x86_64""".r
   private val Arm64 = """arm64|aarch64""".r
+  private val Arm32 = """arm""".r
 
   def cpu_arch: String =
     System.getProperty("os.arch", "") match {
       case X86() => "x86"
       case X86_64() => "x86_64"
       case Arm64() => "arm64"
+      case Arm32() => "arm32"
       case _ => error("Failed to determine CPU architecture")
     }
 
   def os_name: String =
     family match {
       case Family.macos => "darwin"
       case _ => family.toString
     }
 
   lazy val jvm_platform: String = cpu_arch + "-" + os_name
 
 
   /* JVM version */
 
   private val Version = """1\.(\d+)\.0_(\d+)""".r
   lazy val jvm_version: String =
     System.getProperty("java.version") match {
       case Version(a, b) => a + "u" + b
       case a => a
     }
 
 
   /* JVM name */
 
   val jvm_name: String = System.getProperty("java.vm.name", "")
 }