diff --git a/wpilibj/athena.gradle b/wpilibj/athena.gradle
index 539a787e8a..fad622c81e 100644
--- a/wpilibj/athena.gradle
+++ b/wpilibj/athena.gradle
@@ -35,6 +35,7 @@ model {
                 tasks.withType(CppCompile) {
                     dependsOn jniHeaders
                     cppCompiler.args "-DNAMESPACED_PRIORITY"
+                    cppCompiler.args "-DCONFIG_ATHENA"
                     addNiLibraryLinks(linker, targetPlatform)
                     addWpiUtilLibraryLinks(it, linker, targetPlatform)
                 }
diff --git a/wpilibj/src/athena/cpp/lib/CANJNI.cpp b/wpilibj/src/athena/cpp/lib/CANJNI.cpp
index 1dca8e98c9..64fd454569 100644
--- a/wpilibj/src/athena/cpp/lib/CANJNI.cpp
+++ b/wpilibj/src/athena/cpp/lib/CANJNI.cpp
@@ -8,7 +8,9 @@
 #include <assert.h>
 #include <jni.h>
 
+#ifdef CONFIG_ATHENA
 #include "FRC_NetworkCommunication/CANSessionMux.h"
+#endif
 #include "HAL/cpp/Log.h"
 #include "HALUtil.h"
 #include "edu_wpi_first_wpilibj_can_CANJNI.h"
@@ -37,6 +39,7 @@ extern "C" {
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_wpilibj_can_CANJNI_FRCNetCommCANSessionMuxSendMessage(
     JNIEnv *env, jclass, jint messageID, jobject data, jint periodMs) {
+#ifdef CONFIG_ATHENA
   CANJNI_LOG(logDEBUG)
       << "Calling CANJNI FRCNetCommCANSessionMuxSendMessage";
 
@@ -69,6 +72,9 @@ Java_edu_wpi_first_wpilibj_can_CANJNI_FRCNetCommCANSessionMuxSendMessage(
 
   CANJNI_LOG(logDEBUG) << "Status: " << status;
   CheckCANStatus(env, status, messageID);
+#else
+  // TODO: Make this throw
+#endif
 }
 
 static uint8_t buffer[8];
@@ -82,6 +88,7 @@ JNIEXPORT jobject JNICALL
 Java_edu_wpi_first_wpilibj_can_CANJNI_FRCNetCommCANSessionMuxReceiveMessage(
     JNIEnv *env, jclass, jobject messageID, jint messageIDMask,
     jobject timeStamp) {
+#ifdef CONFIG_ATHENA
   CANJNI_LOG(logDEBUG)
       << "Calling CANJNI FRCNetCommCANSessionMuxReceiveMessage";
 
@@ -118,6 +125,10 @@ Java_edu_wpi_first_wpilibj_can_CANJNI_FRCNetCommCANSessionMuxReceiveMessage(
 
   if (!CheckCANStatus(env, status, *messageIDPtr)) return nullptr;
   return env->NewDirectByteBuffer(buffer, dataSize);
+#else
+  // TODO: Make throw
+  return nullptr;
+#endif
 }
 
 }  // extern "C"
diff --git a/wpilibj/src/athena/cpp/lib/HALUtil.cpp b/wpilibj/src/athena/cpp/lib/HALUtil.cpp
index 3f89c72bf3..6aac1c797c 100644
--- a/wpilibj/src/athena/cpp/lib/HALUtil.cpp
+++ b/wpilibj/src/athena/cpp/lib/HALUtil.cpp
@@ -15,7 +15,9 @@
 #include <cstring>
 #include <string>
 
+#ifdef CONFIG_ATHENA
 #include "FRC_NetworkCommunication/CANSessionMux.h"
+#endif
 #include "HAL/HAL.h"
 #include "HAL/DriverStation.h"
 #include "HAL/Errors.h"
@@ -78,7 +80,11 @@ void ThrowHalHandleException(JNIEnv *env, int32_t status) {
   halHandleExCls.Throw(env, buf.c_str());
 }
 
-constexpr const char wpilibjPrefix[] = "edu.wpi.first.wpilibj";
+#ifndef _WIN32
+constexpr const char JNI_wpilibjPrefix[] = "edu.wpi.first.wpilibj";
+#else
+extern const char JNI_wpilibjPrefix[] = "edu.wpi.first.wpilibj";
+#endif
 
 void ReportError(JNIEnv *env, int32_t status, bool do_throw) {
   if (status == 0) return;
@@ -93,7 +99,7 @@ void ReportError(JNIEnv *env, int32_t status, bool do_throw) {
     runtimeExCls.Throw(env, buf.c_str());
   } else {
     std::string func;
-    auto stack = GetJavaStackTrace<wpilibjPrefix>(env, &func);
+    auto stack = GetJavaStackTrace<JNI_wpilibjPrefix>(env, &func);
     HAL_SendError(1, status, 0, message, func.c_str(), stack.c_str(), 1);
   }
 }
@@ -122,7 +128,9 @@ void ReportCANError(JNIEnv *env, int32_t status, int message_id) {
     case kRioStatusSuccess:
       // Everything is ok... don't throw.
       break;
+#ifdef CONFIG_ATHENA
     case ERR_CANSessionMux_InvalidBuffer:
+#endif
     case kRIOStatusBufferInvalidSize: {
       static jmethodID invalidBufConstruct = nullptr;
       if (!invalidBufConstruct)
@@ -133,7 +141,9 @@ void ReportCANError(JNIEnv *env, int32_t status, int message_id) {
       env->Throw(static_cast<jthrowable>(exception));
       break;
     }
+#ifdef CONFIG_ATHENA
     case ERR_CANSessionMux_MessageNotFound:
+#endif
     case kRIOStatusOperationTimedOut: {
       static jmethodID messageNotFoundConstruct = nullptr;
       if (!messageNotFoundConstruct)
@@ -144,7 +154,9 @@ void ReportCANError(JNIEnv *env, int32_t status, int message_id) {
       env->Throw(static_cast<jthrowable>(exception));
       break;
     }
+#ifdef CONFIG_ATHENA
     case ERR_CANSessionMux_NotAllowed:
+#endif
     case kRIOStatusFeatureNotSupported: {
       llvm::SmallString<100> buf;
       llvm::raw_svector_ostream oss(buf);
@@ -152,7 +164,9 @@ void ReportCANError(JNIEnv *env, int32_t status, int message_id) {
       canMessageNotAllowedExCls.Throw(env, buf.c_str());
       break;
     }
+#ifdef CONFIG_ATHENA
     case ERR_CANSessionMux_NotInitialized:
+#endif
     case kRIOStatusResourceNotInitialized: {
       static jmethodID notInitConstruct = nullptr;
       if (!notInitConstruct)
diff --git a/wpilibj/src/athena/cpp/lib/InterruptJNI.cpp b/wpilibj/src/athena/cpp/lib/InterruptJNI.cpp
index 93443487ab..7f37b5382d 100644
--- a/wpilibj/src/athena/cpp/lib/InterruptJNI.cpp
+++ b/wpilibj/src/athena/cpp/lib/InterruptJNI.cpp
@@ -164,7 +164,7 @@ Java_edu_wpi_first_wpilibj_hal_InterruptJNI_cleanInterrupts(
  * Method:    waitForInterrupt
  * Signature: (JD)V
  */
-JNIEXPORT int32_t JNICALL
+JNIEXPORT jint JNICALL
 Java_edu_wpi_first_wpilibj_hal_InterruptJNI_waitForInterrupt(
     JNIEnv* env, jclass, jint interruptHandle, jdouble timeout,
     jboolean ignorePrevious) {