diff --git a/qtest.c b/qtest.c
index 04412ddde1b88f1b4df412f57f6bbc138d436ed8..05cefd280072f631ac46a15d27e7732a4150f6e8 100644
--- a/qtest.c
+++ b/qtest.c
@@ -414,6 +414,7 @@ static void qtest_process_command(CharDriverState *chr, gchar **words)
     } else if (strcmp(words[0], "read") == 0) {
         uint64_t addr, len, i;
         uint8_t *data;
+        char *enc;
 
         g_assert(words[1] && words[2]);
         addr = strtoull(words[1], NULL, 0);
@@ -422,14 +423,16 @@ static void qtest_process_command(CharDriverState *chr, gchar **words)
         data = g_malloc(len);
         cpu_physical_memory_read(addr, data, len);
 
-        qtest_send_prefix(chr);
-        qtest_send(chr, "OK 0x");
+        enc = g_malloc(2 * len + 1);
         for (i = 0; i < len; i++) {
-            qtest_sendf(chr, "%02x", data[i]);
+            sprintf(&enc[i * 2], "%02x", data[i]);
         }
-        qtest_send(chr, "\n");
+
+        qtest_send_prefix(chr);
+        qtest_sendf(chr, "OK 0x%s\n", enc);
 
         g_free(data);
+        g_free(enc);
     } else if (strcmp(words[0], "b64read") == 0) {
         uint64_t addr, len;
         uint8_t *data;
diff --git a/tests/libqtest.c b/tests/libqtest.c
index 055aad69e0f06421428b1e5e245653d1cc34a194..e5188e0327a2b9c7d1d3ebc4ecd930a1f66e5523 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -730,13 +730,15 @@ void qtest_memwrite(QTestState *s, uint64_t addr, const void *data, size_t size)
 {
     const uint8_t *ptr = data;
     size_t i;
+    char *enc = g_malloc(2 * size + 1);
 
-    qtest_sendf(s, "write 0x%" PRIx64 " 0x%zx 0x", addr, size);
     for (i = 0; i < size; i++) {
-        qtest_sendf(s, "%02x", ptr[i]);
+        sprintf(&enc[i * 2], "%02x", ptr[i]);
     }
-    qtest_sendf(s, "\n");
+
+    qtest_sendf(s, "write 0x%" PRIx64 " 0x%zx 0x%s\n", addr, size, enc);
     qtest_rsp(s, 0);
+    g_free(enc);
 }
 
 void qtest_memset(QTestState *s, uint64_t addr, uint8_t pattern, size_t size)