diff --git a/components/log/host_test/log_test/main/log_test.cpp b/components/log/host_test/log_test/main/log_test.cpp
index 40da7d3763..a9c2a12435 100644
--- a/components/log/host_test/log_test/main/log_test.cpp
+++ b/components/log/host_test/log_test/main/log_test.cpp
@@ -204,6 +204,31 @@ TEST_CASE("log buffer")
     CHECK(regex_search(fix.get_print_buffer_string(), buffer_regex));
 }
 
+TEST_CASE("log bytes > 127")
+{
+    PrintFixture fix(ESP_LOG_INFO);
+    const uint8_t buffer[] = {
+        0xff, 0x80,
+    };
+    ESP_LOG_BUFFER_HEX(TEST_TAG, buffer, sizeof(buffer));
+    const std::regex buffer_regex("I \\([0-9]*\\) test: ff 80", std::regex::ECMAScript);
+    CHECK(regex_search(fix.get_print_buffer_string(), buffer_regex));
+}
+
+TEST_CASE("log buffer dump")
+{
+    PrintFixture fix(ESP_LOG_INFO);
+    const uint8_t buffer[] = {
+        0x00, 0x00, 0x00, 0x00, 0x05, 0x06, 0x07, 0x08,
+        0xff, 0xfe, 0xfd, 0xfc, 0xfb, 0xfa, 0xf9, 0xf8
+    };
+    ESP_LOG_BUFFER_HEXDUMP(TEST_TAG, buffer, sizeof(buffer), ESP_LOG_INFO);
+    const std::regex buffer_regex("I \\([0-9]*\\) test: 0x[0-9a-f]+\\s+"
+                                  "00 00 00 00 05 06 07 08  ff fe fd fc fb fa f9 f8 "
+                                  "\\s+|[\\.]{16}|", std::regex::ECMAScript);
+    CHECK(regex_search(fix.get_print_buffer_string(), buffer_regex));
+}
+
 TEST_CASE("rom printf")
 {
     PutcFixture fix;
diff --git a/components/log/log_buffers.c b/components/log/log_buffers.c
index bdbb1437c6..bef3072455 100644
--- a/components/log/log_buffers.c
+++ b/components/log/log_buffers.c
@@ -49,7 +49,7 @@ void esp_log_buffer_hex_internal(const char *tag, const void *buffer, uint16_t b
         }
 
         for (int i = 0; i < bytes_cur_line; i ++) {
-            sprintf(hex_buffer + 3 * i, "%02x ", ptr_line[i]);
+            sprintf(hex_buffer + 3 * i, "%02x ", (unsigned char) ptr_line[i]);
         }
         ESP_LOG_LEVEL(log_level, tag, "%s", hex_buffer);
         buffer += bytes_cur_line;
@@ -101,7 +101,7 @@ void esp_log_buffer_hexdump_internal(const char *tag, const void *buffer, uint16
     const char *ptr_line;
     //format: field[length]
     // ADDR[10]+"   "+DATA_HEX[8*3]+" "+DATA_HEX[8*3]+"  |"+DATA_CHAR[8]+"|"
-    char hd_buffer[10 + 3 + BYTES_PER_LINE * 3 + 3 + BYTES_PER_LINE + 1 + 1];
+    char hd_buffer[2 + sizeof(void *) * 2 + 3 + BYTES_PER_LINE * 3 + 1 + 3 + BYTES_PER_LINE + 1 + 1];
     char *ptr_hd;
     int bytes_cur_line;
 
@@ -126,7 +126,7 @@ void esp_log_buffer_hexdump_internal(const char *tag, const void *buffer, uint16
                 ptr_hd += sprintf(ptr_hd, " ");
             }
             if (i < bytes_cur_line) {
-                ptr_hd += sprintf(ptr_hd, " %02x", ptr_line[i]);
+                ptr_hd += sprintf(ptr_hd, " %02x", (unsigned char) ptr_line[i]);
             } else {
                 ptr_hd += sprintf(ptr_hd, "   ");
             }