diff --git a/src/libopensc/iso7816.c b/src/libopensc/iso7816.c
index 8cb9e6b6..d35ef086 100644
--- a/src/libopensc/iso7816.c
+++ b/src/libopensc/iso7816.c
@@ -491,6 +491,9 @@ static int iso7816_get_challenge(sc_card_t *card, u8 *rnd, size_t len)
 	sc_apdu_t apdu;
 	u8 buf[10];
 
+	if (!rnd)
+		return SC_ERROR_INVALID_ARGUMENTS;
+
 	sc_format_apdu(card, &apdu, SC_APDU_CASE_2_SHORT,
 		       0x84, 0x00, 0x00);
 	apdu.le = 8;
diff --git a/src/pkcs11/pkcs11-object.c b/src/pkcs11/pkcs11-object.c
index 5137dfc2..05e8622e 100644
--- a/src/pkcs11/pkcs11-object.c
+++ b/src/pkcs11/pkcs11-object.c
@@ -957,7 +957,7 @@ CK_RV C_SeedRandom(CK_SESSION_HANDLE hSession,  /* the session's handle */
 	if (rv == CKR_OK) {
 		slot = session->slot;
 		if (slot->card->framework->seed_random == NULL)
-			rv = CKR_FUNCTION_NOT_SUPPORTED;
+			rv = CKR_RANDOM_SEED_NOT_SUPPORTED;
 		else
 			rv = slot->card->framework->seed_random(slot->card, pSeed, ulSeedLen);
 	}
@@ -982,7 +982,7 @@ CK_RV C_GenerateRandom(CK_SESSION_HANDLE hSession,    /* the session's handle */
 	if (rv == CKR_OK) {
 		slot = session->slot;
 		if (slot->card->framework->get_random == NULL)
-			rv = CKR_FUNCTION_NOT_SUPPORTED;
+			rv = CKR_RANDOM_NO_RNG;
 		else
 			rv = slot->card->framework->get_random(slot->card, RandomData, ulRandomLen);
 	}
diff --git a/src/pkcs11/pkcs11-spy.c b/src/pkcs11/pkcs11-spy.c
index 9e945cfd..6cb29eca 100644
--- a/src/pkcs11/pkcs11-spy.c
+++ b/src/pkcs11/pkcs11-spy.c
@@ -1376,6 +1376,7 @@ CK_RV C_WaitForSlotEvent(CK_FLAGS flags,
 {
   CK_RV rv;
   enter("C_WaitForSlotEvent");
+  spy_dump_ulong_in("flags", flags);
   rv = po->C_WaitForSlotEvent(flags, pSlot, pRserved);
   return retne(rv);
 }
diff --git a/src/tools/pkcs11-tool.c b/src/tools/pkcs11-tool.c
index 2b076cba..790749fd 100644
--- a/src/tools/pkcs11-tool.c
+++ b/src/tools/pkcs11-tool.c
@@ -2978,12 +2978,13 @@ static int test_random(CK_SLOT_ID slot)
 	if (rv != CKR_OK)
 		p11_fatal("C_OpenSession", rv);
 
-	rv = p11->C_SeedRandom(session, seed1, 10);
-	if (rv == CKR_RANDOM_NO_RNG || rv == CKR_FUNCTION_NOT_SUPPORTED) {
-		printf("  not implemented\n");
+	rv = p11->C_SeedRandom(session, seed1, 100);
+	if (rv == CKR_RANDOM_NO_RNG) {
+		printf("  RNG not available\n");
 		return 0;
 	}
-	if (rv == CKR_RANDOM_SEED_NOT_SUPPORTED)
+
+	if (rv == CKR_RANDOM_SEED_NOT_SUPPORTED || rv == CKR_FUNCTION_NOT_SUPPORTED)
 		printf("  seeding (C_SeedRandom) not supported\n");
 	else if (rv != CKR_OK) {
 		p11_perror("C_SeedRandom", rv);
@@ -2998,19 +2999,19 @@ static int test_random(CK_SLOT_ID slot)
 
 	rv = p11->C_GenerateRandom(session, buf1, 100);
 	if (rv != CKR_OK) {
-		p11_perror("C_GenerateRandom", rv);
+		p11_perror("C_GenerateRandom(buf1,100)", rv);
 		return 1;
 	}
 
 	rv = p11->C_GenerateRandom(session, buf1, 0);
 	if (rv != CKR_OK) {
-		p11_perror("C_GenerateRandom(,,0)", rv);
+		p11_perror("C_GenerateRandom(buf1,0)", rv);
 		return 1;
 	}
 
-	rv = p11->C_GenerateRandom(session, NULL, 100);
+	rv = p11->C_GenerateRandom(session, buf2, 100);
 	if (rv != CKR_OK) {
-		p11_perror("C_GenerateRandom(,NULL,)", rv);
+		p11_perror("C_GenerateRandom(buf2,100)", rv);
 		return 1;
 	}