diff --git a/src/com/squareup/wire/EnumAdapter.java b/src/com/squareup/wire/EnumAdapter.java
new file mode 100644
index 0000000..e39c720
--- /dev/null
+++ b/src/com/squareup/wire/EnumAdapter.java
@@ -0,0 +1,37 @@
+package com.squareup.wire;
+
+import java.io.IOException;
+
+/**
+ * Compatibility shim. The stock light_camera APK's generated {@code ltpb} enum adapters
+ * (e.g. {@code ViewPreferences$AspectRatio$ProtoAdapter_AspectRatio}) extend
+ * {@code com.squareup.wire.EnumAdapter} and call its {@code (Class)} constructor + override
+ * {@code fromValue(int)}. That abstract base class is NOT present in any released
+ * wire-runtime 2.0.0–2.2.0 (which ship the reflection-based {@code RuntimeEnumAdapter} instead),
+ * so {@code download-libs.sh}'s wire-runtime-2.2.0 lacks it and the adapters fail to link at
+ * runtime ({@code NoClassDefFoundError} during the first capture's image-save path).
+ *
+ * This restores the small abstract base, implemented on top of 2.2.0's {@link ProtoAdapter}
+ * exactly like {@code RuntimeEnumAdapter}: an enum is wire-encoded as a VARINT of its value.
+ */
+public abstract class EnumAdapter<E extends WireEnum> extends ProtoAdapter<E> {
+  protected EnumAdapter(Class<E> type) {
+    super(FieldEncoding.VARINT, type);
+  }
+
+  /** Subclasses (generated {@code ProtoAdapter_*}) map a proto int back to the enum constant. */
+  protected abstract E fromValue(int value);
+
+  @Override public int encodedSize(E value) {
+    return ProtoWriter.varint32Size(value.getValue());
+  }
+
+  @Override public void encode(ProtoWriter writer, E value) throws IOException {
+    writer.writeVarint32(value.getValue());
+  }
+
+  @Override public E decode(ProtoReader reader) throws IOException {
+    int value = reader.readVarint32();
+    return fromValue(value);
+  }
+}