diff --git a/subsys/storage/stream/stream_flash.c b/subsys/storage/stream/stream_flash.c
index 55a10f51345..bee7a5beed3 100644
--- a/subsys/storage/stream/stream_flash.c
+++ b/subsys/storage/stream/stream_flash.c
@@ -108,6 +108,9 @@ static int flash_sync(struct stream_flash_ctx *ctx)
 {
 	int rc = 0;
 	size_t write_addr = ctx->offset + ctx->bytes_written;
+	size_t buf_bytes_aligned;
+	size_t fill_length;
+	uint8_t filler;
 
 
 	if (ctx->buf_bytes == 0) {
@@ -125,7 +128,18 @@ static int flash_sync(struct stream_flash_ctx *ctx)
 		}
 	}
 
-	rc = flash_write(ctx->fdev, write_addr, ctx->buf, ctx->buf_bytes);
+	fill_length = flash_get_write_block_size(ctx->fdev);
+	if (ctx->buf_bytes % fill_length) {
+		fill_length -= ctx->buf_bytes % fill_length;
+		filler = flash_get_parameters(ctx->fdev)->erase_value;
+
+		memset(ctx->buf + ctx->buf_bytes, filler, fill_length);
+	} else {
+		fill_length = 0;
+	}
+
+	buf_bytes_aligned = ctx->buf_bytes + fill_length;
+	rc = flash_write(ctx->fdev, write_addr, ctx->buf, buf_bytes_aligned);
 
 	if (rc != 0) {
 		LOG_ERR("flash_write error %d offset=0x%08zx", rc,
@@ -167,8 +181,6 @@ int stream_flash_buffered_write(struct stream_flash_ctx *ctx, const uint8_t *dat
 	int processed = 0;
 	int rc = 0;
 	int buf_empty_bytes;
-	size_t fill_length;
-	uint8_t filler;
 
 	if (!ctx) {
 		return -EFAULT;
@@ -201,23 +213,7 @@ int stream_flash_buffered_write(struct stream_flash_ctx *ctx, const uint8_t *dat
 	}
 
 	if (flush && ctx->buf_bytes > 0) {
-		fill_length = flash_get_write_block_size(ctx->fdev);
-		if (ctx->buf_bytes % fill_length) {
-			fill_length -= ctx->buf_bytes % fill_length;
-			filler = flash_get_parameters(ctx->fdev)->erase_value;
-
-			memset(ctx->buf + ctx->buf_bytes, filler, fill_length);
-			ctx->buf_bytes += fill_length;
-		} else {
-			fill_length = 0;
-		}
-
 		rc = flash_sync(ctx);
-		if (rc == 0) {
-			ctx->bytes_written -= fill_length;
-		} else {
-			ctx->buf_bytes -= fill_length;
-		}
 	}
 
 	return rc;
diff --git a/tests/subsys/storage/stream/stream_flash/src/main.c b/tests/subsys/storage/stream/stream_flash/src/main.c
index 2f98a826b3b..93d803e6db6 100644
--- a/tests/subsys/storage/stream/stream_flash/src/main.c
+++ b/tests/subsys/storage/stream/stream_flash/src/main.c
@@ -196,6 +196,11 @@ static void test_stream_flash_buffered_write_unaligned(void)
 			       0, stream_flash_callback);
 	zassert_equal(rc, 0, "expected success");
 
+	/* Trigger verification in callback */
+	cb_buf = buf;
+	cb_len = BUF_LEN - 1;
+	cb_offset = FLASH_BASE + BUF_LEN;
+
 	/* Test unaligned data size */
 	rc = stream_flash_buffered_write(&ctx, write_buf, BUF_LEN - 1, true);
 	zassert_equal(rc, 0, "expected success");