fix crash in volk

src/backend/core/mmio/Audio.hpp

@@ -13,10 +13,12 @@ struct AudioDevice {
   void PushSample(float, float, float, float);
   void AdjustSampleRate(int);
   void LockMutex() {
-    SDL_LockMutex(audioStreamMutex);
+    if(audioStreamMutex)
+      SDL_LockMutex(audioStreamMutex);
   }
   void UnlockMutex() {
-    SDL_UnlockMutex(audioStreamMutex);
+    if (audioStreamMutex)
+      SDL_UnlockMutex(audioStreamMutex);
   }
 
   SDL_AudioStream* GetStream() { return audioStream; }

src/backend/core/mmio/PI.cpp

@@ -468,7 +468,7 @@ void PI::Write(u32 addr, u32 val) {
 
       for(u32 i = 0; i < len; i++) {
         u32 addr = BYTE_ADDRESS(dramAddrInternal + i) & RDRAM_DSIZE;
-        if (addr < mem.mmio.rdp.rdram.size()) {
+        if (addr < RDRAM_SIZE) {
           mem.mmio.rdp.rdram[addr] = BusRead<u8, true>(cartAddrInternal + i);
         }
       }