diff --git a/samples/drivers/soc_flash_nrf5/prj.conf b/samples/drivers/soc_flash_nrf5/prj.conf
index 2b15c897a54..ddba4985063 100644
--- a/samples/drivers/soc_flash_nrf5/prj.conf
+++ b/samples/drivers/soc_flash_nrf5/prj.conf
@@ -1,3 +1,4 @@
 CONFIG_STDOUT_CONSOLE=y
 CONFIG_FLASH=y
 CONFIG_SOC_FLASH_NRF5=y
+CONFIG_SYS_LOG=y
diff --git a/samples/drivers/soc_flash_nrf5/src/main.c b/samples/drivers/soc_flash_nrf5/src/main.c
index 377d3665795..5ea51148f21 100644
--- a/samples/drivers/soc_flash_nrf5/src/main.c
+++ b/samples/drivers/soc_flash_nrf5/src/main.c
@@ -18,13 +18,9 @@
 #include <zephyr.h>
 #include <flash.h>
 #include <device.h>
-#if defined(CONFIG_STDOUT_CONSOLE)
-#include <stdio.h>
-#define PRINT           printf
-#else
-#include <misc/printk.h>
-#define PRINT           printk
-#endif
+
+#define SYS_LOG_LEVEL SYS_LOG_LEVEL_INFO
+#include <misc/sys_log.h>
 
 /* Offset between pages */
 #define FLASH_TEST_OFFSET 0x40000
@@ -45,79 +41,83 @@ void main(void)
 	uint32_t buf_word = 0;
 	uint32_t i, offset;
 
-	PRINT("\nNordic nRF5 Flash Testing\n");
-	PRINT("=========================\n");
+	SYS_LOG_INF("\nNordic nRF5 Flash Testing");
+	SYS_LOG_INF("=========================");
 
 	flash_dev = device_get_binding("NRF5_FLASH");
 
 	if (!flash_dev) {
-		PRINT("Nordic nRF5 flash driver was not found!\n");
+		SYS_LOG_ERR("Nordic nRF5 flash driver was not found!");
 		return;
 	}
 
-	PRINT("\nTest 1: Flash erase page at 0x%x\n", FLASH_TEST_OFFSET);
+	SYS_LOG_INF("\nTest 1: Flash erase page at 0x%x", FLASH_TEST_OFFSET);
 	if (flash_erase(flash_dev, FLASH_TEST_OFFSET, FLASH_PAGE_SIZE) != 0) {
-		PRINT("   Flash erase failed!\n");
+		SYS_LOG_INF("   Flash erase failed!");
 	} else {
-		PRINT("   Flash erase succeeded!\n");
+		SYS_LOG_INF("   Flash erase succeeded!");
 	}
 
-	PRINT("\nTest 2: Flash write (word array 1)\n");
+	SYS_LOG_INF("\nTest 2: Flash write (word array 1)");
 	flash_write_protection_set(flash_dev, false);
 	for (i = 0; i < TEST_DATA_LEN; i++) {
 		offset = FLASH_TEST_OFFSET + (i << 2);
-		PRINT("   Attempted to write %x at 0x%x\n", buf_array_1[i],
-				offset);
+		SYS_LOG_INF("   Attempted to write %x at 0x%x",
+			    buf_array_1[i], offset);
 		if (flash_write(flash_dev, offset, &buf_array_1[i],
 					TEST_DATA_LEN) != 0) {
-			PRINT("   Flash write failed!\n");
+			SYS_LOG_INF("   Flash write failed!");
 			return;
 		}
-		PRINT("   Attempted to read 0x%x\n", offset);
+		SYS_LOG_INF("   Attempted to read 0x%x", offset);
 		if (flash_read(flash_dev, offset, &buf_word,
 					TEST_DATA_LEN) != 0) {
-			PRINT("   Flash read failed!\n");
+			SYS_LOG_INF("   Flash read failed!");
 			return;
 		}
-		PRINT("   Data read: %x\n", buf_word);
+		SYS_LOG_INF("   Data read: %x", buf_word);
 		if (buf_array_1[i] == buf_word) {
-			PRINT("   Data read matches data written. Good!\n");
+			SYS_LOG_INF("   Data read matches data written. "
+				    "Good!");
 		} else {
-			PRINT("   Data read does not match data written!\n");
+			SYS_LOG_INF("   Data read does not match data "
+				    "written!");
 		}
 	}
 	flash_write_protection_set(flash_dev, true);
 
 	offset = FLASH_TEST_OFFSET - FLASH_PAGE_SIZE * 2;
-	PRINT("\nTest 3: Flash erase (4 pages at 0x%x)\n", offset);
+	SYS_LOG_INF("\nTest 3: Flash erase (4 pages at 0x%x)", offset);
 	if (flash_erase(flash_dev, offset, FLASH_PAGE_SIZE * 4) != 0) {
-		PRINT("   Flash erase failed!\n");
+		SYS_LOG_INF("   Flash erase failed!");
 	} else {
-		PRINT("   Flash erase succeeded!\n");
+		SYS_LOG_INF("   Flash erase succeeded!");
 	}
 
-	PRINT("\nTest 4: Flash write (word array 2)\n");
+	SYS_LOG_INF("\nTest 4: Flash write (word array 2)");
 	flash_write_protection_set(flash_dev, false);
 	for (i = 0; i < TEST_DATA_LEN; i++) {
 		offset = FLASH_TEST_OFFSET + (i << 2);
-		PRINT("   Attempted to write %x at 0x%x\n", buf_array_2[i],
-				offset);
+		SYS_LOG_INF("   Attempted to write %x at 0x%x",
+			    buf_array_2[i], offset);
 		if (flash_write(flash_dev, offset, &buf_array_2[i],
 					TEST_DATA_LEN) != 0) {
-			PRINT("   Flash write failed!\n");
+			SYS_LOG_INF("   Flash write failed!");
 			return;
 		}
-		PRINT("   Attempted to read 0x%x\n", offset);
+		SYS_LOG_INF("   Attempted to read 0x%x", offset);
 		if (flash_read(flash_dev, offset, &buf_word,
 					TEST_DATA_LEN) != 0) {
-			PRINT("   Flash read failed!\n");
+			SYS_LOG_INF("   Flash read failed!");
 			return;
 		}
-		PRINT("   Data read: %x\n", buf_word);
+		SYS_LOG_INF("   Data read: %x", buf_word);
 		if (buf_array_2[i] == buf_word) {
-			PRINT("   Data read matches data written. Good!\n");
+			SYS_LOG_INF("   Data read matches data written. "
+				    "Good!");
 		} else {
-			PRINT("   Data read does not match data written!\n");
+			SYS_LOG_INF("   Data read does not match data "
+				    "written!");
 		}
 	}
 	flash_write_protection_set(flash_dev, true);
diff --git a/samples/drivers/spi_flash/prj.conf b/samples/drivers/spi_flash/prj.conf
index 9f1a32ff484..5a5597b05bb 100644
--- a/samples/drivers/spi_flash/prj.conf
+++ b/samples/drivers/spi_flash/prj.conf
@@ -4,3 +4,4 @@ CONFIG_SPI=y
 CONFIG_GPIO=y
 CONFIG_SPI_CS_GPIO=y
 CONFIG_SPI_0_CS_GPIO_PIN=24
+CONFIG_SYS_LOG=y
diff --git a/samples/drivers/spi_flash/src/main.c b/samples/drivers/spi_flash/src/main.c
index 87124831005..737daee21bc 100644
--- a/samples/drivers/spi_flash/src/main.c
+++ b/samples/drivers/spi_flash/src/main.c
@@ -17,13 +17,8 @@
 #include <zephyr.h>
 #include <flash.h>
 #include <device.h>
-#if defined(CONFIG_STDOUT_CONSOLE)
-#include <stdio.h>
-#define PRINT           printf
-#else
-#include <misc/printk.h>
-#define PRINT           printk
-#endif
+#define SYS_LOG_LEVEL SYS_LOG_LEVEL_INFO
+#include <misc/sys_log.h>
 
 #define FLASH_TEST_REGION_OFFSET 0xff000
 #define FLASH_SECTOR_SIZE        4096
@@ -36,13 +31,13 @@ void main(void)
 	struct device *flash_dev;
 	uint8_t buf[TEST_DATA_LEN];
 
-	PRINT("\nW25QXXDV SPI flash testing\n");
-	PRINT("==========================\n");
+	SYS_LOG_INF("\nW25QXXDV SPI flash testing");
+	SYS_LOG_INF("==========================");
 
 	flash_dev = device_get_binding("W25QXXDV");
 
 	if (!flash_dev) {
-		PRINT("SPI flash driver was not found!\n");
+		SYS_LOG_ERR("SPI flash driver was not found!");
 		return;
 	}
 
@@ -51,38 +46,39 @@ void main(void)
 	 * on write protection automatically after completion of write and
 	 * erase operations.
 	 */
-	PRINT("\nTest 1: Flash erase\n");
+	SYS_LOG_INF("\nTest 1: Flash erase");
 	flash_write_protection_set(flash_dev, false);
 	if (flash_erase(flash_dev,
 			FLASH_TEST_REGION_OFFSET,
 			FLASH_SECTOR_SIZE) != 0) {
-		PRINT("   Flash erase failed!\n");
+		SYS_LOG_INF("   Flash erase failed!");
 	} else {
-		PRINT("   Flash erase succeeded!\n");
+		SYS_LOG_INF("   Flash erase succeeded!");
 	}
 
-	PRINT("\nTest 2: Flash write\n");
+	SYS_LOG_INF("\nTest 2: Flash write");
 	flash_write_protection_set(flash_dev, false);
 
 	buf[0] = TEST_DATA_BYTE_0;
 	buf[1] = TEST_DATA_BYTE_1;
-	PRINT("   Attempted to write %x %x\n", buf[0], buf[1]);
+	SYS_LOG_INF("   Attempted to write %x %x", buf[0], buf[1]);
 	if (flash_write(flash_dev, FLASH_TEST_REGION_OFFSET, buf,
 	    TEST_DATA_LEN) != 0) {
-		PRINT("   Flash write failed!\n");
+		SYS_LOG_INF("   Flash write failed!");
 		return;
 	}
 
 	if (flash_read(flash_dev, FLASH_TEST_REGION_OFFSET, buf,
 	    TEST_DATA_LEN) != 0) {
-		PRINT("   Flash read failed!\n");
+		SYS_LOG_INF("   Flash read failed!");
 		return;
 	}
-	PRINT("   Data read %x %x\n", buf[0], buf[1]);
+	SYS_LOG_INF("   Data read %x %x", buf[0], buf[1]);
 
 	if ((buf[0] == TEST_DATA_BYTE_0) && (buf[1] == TEST_DATA_BYTE_1)) {
-		PRINT("   Data read matches with data written. Good!!\n");
+		SYS_LOG_INF("   Data read matches with data written. Good!!");
 	} else {
-		PRINT("   Data read does not match with data written!!\n");
+		SYS_LOG_INF("   Data read does not match with data "
+			    "written!!");
 	}
 }