diff --git a/src/add-ons/kernel/drivers/audio/echo/multi.cpp b/src/add-ons/kernel/drivers/audio/echo/multi.cpp
index 6b5dfcda1b..17dbb06658 100644
--- a/src/add-ons/kernel/drivers/audio/echo/multi.cpp
+++ b/src/add-ons/kernel/drivers/audio/echo/multi.cpp
@@ -255,7 +255,7 @@ echo_get_mix(echo_dev *card, multi_mix_value_info * mmvi)
 	multi_mixer_control *control = NULL;
 	for (i = 0; i < mmvi->item_count; i++) {
 		id = mmvi->values[i].id - MULTI_CONTROL_FIRSTID;
-		if (id < 0 || id >= card->multi.control_count) {
+		if (id < 0 || (uint32)id >= card->multi.control_count) {
 			PRINT(("echo_get_mix : invalid control id requested : %" B_PRIu32
 				"\n", id));
 			continue;
@@ -297,7 +297,7 @@ echo_set_mix(echo_dev *card, multi_mix_value_info * mmvi)
 	multi_mixer_control *control = NULL;
 	for (i = 0; i < mmvi->item_count; i++) {
 		id = mmvi->values[i].id - MULTI_CONTROL_FIRSTID;
-		if (id < 0 || id >= card->multi.control_count) {
+		if (id < 0 || (uint32)id >= card->multi.control_count) {
 			PRINT(("echo_set_mix : invalid control id requested : %" B_PRIu32
 				"\n", id));
 			continue;
@@ -308,7 +308,7 @@ echo_set_mix(echo_dev *card, multi_mix_value_info * mmvi)
 			multi_mixer_control *control2 = NULL;
 			if (i + 1 < mmvi->item_count) {
 				id = mmvi->values[i + 1].id - MULTI_CONTROL_FIRSTID;
-				if (id < 0 || id >= card->multi.control_count) {
+				if (id < 0 || (uint32)id >= card->multi.control_count) {
 					PRINT(("echo_set_mix : invalid control id requested : %"
 						B_PRIu32 "\n", id));
 				} else {
diff --git a/src/add-ons/kernel/drivers/audio/echo/util.c b/src/add-ons/kernel/drivers/audio/echo/util.c
index b76abf46d7..d4b4648d64 100644
--- a/src/add-ons/kernel/drivers/audio/echo/util.c
+++ b/src/add-ons/kernel/drivers/audio/echo/util.c
@@ -114,7 +114,7 @@ map_mem(void **log, phys_addr_t phy, size_t size, const char *name)
 	size = round_to_pagesize(size + offset);
 	area = map_physical_memory(name, phyadr, size, B_ANY_KERNEL_ADDRESS,
 		B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA, &mapadr);
-	*log = mapadr + offset;
+	*log = (void *)((uintptr_t)mapadr + (uintptr_t)offset);
 
 	LOG(("physical = %p, logical = %p, offset = %#x, phyadr = %p, mapadr = %p, size = %#x, area = %#x\n",
 		phy, *log, offset, phyadr, mapadr, size, area));