diff --git a/tools/emulator/opengl/host/libs/libOpenglRender/FBConfig.cpp b/tools/emulator/opengl/host/libs/libOpenglRender/FBConfig.cpp
index fdf5433be..7c8edc0f6 100644
--- a/tools/emulator/opengl/host/libs/libOpenglRender/FBConfig.cpp
+++ b/tools/emulator/opengl/host/libs/libOpenglRender/FBConfig.cpp
@@ -268,14 +268,14 @@ int FBConfig::chooseConfig(FrameBuffer *fb, EGLint * attribs, uint32_t * configs
     //
     uint32_t nVerifiedCfgs = 0;
     for (int matchedIdx=0; matchedIdx<nConfigs; matchedIdx++) {
-        if ((configs_size > 0) && (nVerifiedCfgs >= configs_size)) break; //We have enouhgt configs
+        if ((configs != NULL) && (configs_size > 0) && (nVerifiedCfgs >= configs_size)) break; //We have enouhgt configs
         int sCfgId;
         s_egl.eglGetConfigAttrib(dpy, matchedConfigs[matchedIdx], EGL_CONFIG_ID, &sCfgId);
         for (int fbIdx=0; fbIdx<s_numConfigs; fbIdx++) {
             int dCfgId = s_fbConfigs[fbIdx]->m_attribValues[4]; //CONFIG_ID
             if (sCfgId == dCfgId) {
                 //This config matches the requested attributes and filtered into fbConfigs, so we're happy with it
-                if (nVerifiedCfgs < configs_size) {
+                if (configs && nVerifiedCfgs < configs_size) {
                     configs[nVerifiedCfgs] = fbIdx;
                 }
                 nVerifiedCfgs++;
diff --git a/tools/emulator/opengl/system/OpenglSystemCommon/QemuPipeStream.cpp b/tools/emulator/opengl/system/OpenglSystemCommon/QemuPipeStream.cpp
index b632d84f4..50c3d8bb1 100644
--- a/tools/emulator/opengl/system/OpenglSystemCommon/QemuPipeStream.cpp
+++ b/tools/emulator/opengl/system/OpenglSystemCommon/QemuPipeStream.cpp
@@ -117,7 +117,7 @@ const unsigned char *QemuPipeStream::readFully(void *buf, size_t len)
     //DBG(">> QemuPipeStream::readFully %d\n", len);
     if (!valid()) return NULL;
     if (!buf) {
-        ERR("QemuPipeStream::readFully failed, buf=NULL, len %d", len);
+        if (len>0) ERR("QemuPipeStream::readFully failed, buf=NULL, len %d", len);
         return NULL;  // do not allow NULL buf in that implementation
     }
     size_t res = len;
diff --git a/tools/emulator/opengl/system/egl/egl.cpp b/tools/emulator/opengl/system/egl/egl.cpp
index f8633fdca..79fffe96e 100644
--- a/tools/emulator/opengl/system/egl/egl.cpp
+++ b/tools/emulator/opengl/system/egl/egl.cpp
@@ -808,7 +808,12 @@ EGLBoolean eglQuerySurface(EGLDisplay dpy, EGLSurface eglSurface, EGLint attribu
         case EGL_SWAP_BEHAVIOR:
             *value = surface->getSwapBehavior();
             break;
-            //TODO: complete other attributes
+        case EGL_LARGEST_PBUFFER:
+            // not modified for a window or pixmap surface
+            // and we ignore it when creating a PBuffer surface (default is EGL_FALSE)
+            if (surface->getSurfaceType() & EGL_PBUFFER_BIT) *value = EGL_FALSE;
+            break;
+        //TODO: complete other attributes
         default:
             LOGE("eglQuerySurface %x  EGL_BAD_ATTRIBUTE", attribute);
             ret = setErrorFunc(EGL_BAD_ATTRIBUTE, EGL_FALSE);
@@ -987,9 +992,8 @@ EGLBoolean eglMakeCurrent(EGLDisplay dpy, EGLSurface draw, EGLSurface read, EGLC
     //
     EGLThreadInfo *tInfo = getEGLThreadInfo();
     if (tInfo->currentContext == context &&
-        context &&
-        context->draw == draw &&
-        context->read == read) {
+        (context == NULL ||
+        (context && context->draw == draw && context->read == read))) {
         return EGL_TRUE;
     }
 
diff --git a/tools/emulator/opengl/system/renderControl_enc/renderControl.attrib b/tools/emulator/opengl/system/renderControl_enc/renderControl.attrib
index 7baaf0752..c51ae0eef 100644
--- a/tools/emulator/opengl/system/renderControl_enc/renderControl.attrib
+++ b/tools/emulator/opengl/system/renderControl_enc/renderControl.attrib
@@ -28,6 +28,7 @@ rcChooseConfig
     dir attribs in
 	len attribs attribs_size
 	dir configs out
+    var_flag configs nullAllowed
 	len configs configs_size*sizeof(uint32_t)
 
 rcReadColorBuffer