Found that RPi 32-bit version was missing; punting at a configuration that may work based on prior efforts.

app/gui-swt-linux-arm/build.gradle

@@ -0,0 +1,38 @@
+plugins {
+    id 'org.springframework.boot' version "$springBoot"
+    id 'application'
+}
+
+sourceCompatibility = 11
+targetCompatibility = 11
+
+repositories {
+    mavenCentral()
+    flatDir {
+        // Raspberry Pi 32-bit library
+        dirs project(':').projectDir.absolutePath + "/swt-lib"
+    }
+}
+
+dependencies {
+    implementation project(':lib:ac-swt-common')
+
+    // This is a special case until 32-bit SWT libraries become available.
+    implementation("org.eclipse.platform:org.eclipse.swt.gtk.linux.arm:3.8.2") {
+        exclude group: "org.eclipse.platform", module: "org.eclipse.swt"
+    }
+}
+
+application {
+    mainClass = 'com.webcodepro.applecommander.ui.swt.SwtAppleCommander'
+}
+
+bootJar {
+    archiveBaseName = 'AppleCommander'
+    archiveAppendix = 'linux-arm'
+    manifest {
+        attributes 'Implementation-Title': 'AppleCommander (Linux Arm)',
+                   'Implementation-Version': archiveVersion
+    }
+    from('../../LICENSE')
+}

lib/ac-swt-common/build.gradle

@@ -7,6 +7,10 @@ targetCompatibility = 11
 
 repositories {
     mavenCentral()
+    flatDir {
+        // Raspberry Pi 32-bit library
+        dirs project(':').projectDir.absolutePath + "/swt-lib"
+    }
 }
 
 dependencies {

settings.gradle

@@ -8,5 +8,6 @@ include ':app:gui-swing'
 include ':app:gui-swt-macosx-aarch64'
 include ':app:gui-swt-macosx-x86_64'
 include ':app:gui-swt-linux-aarch64'
+include ':app:gui-swt-linux-arm'
 include ':app:gui-swt-linux-x86_64'
 include ':app:gui-swt-win32-x86_64'