diff --git a/radio.c b/radio.c
index 5730130..d613c90 100644
--- a/radio.c
+++ b/radio.c
@@ -49,6 +49,7 @@ static struct {
     { "ZN><:",      &radio_rt27d },     // Radtel RT-27D
     { "BF-5R",      &radio_rd5r },      // Baofeng RD-5R
     { "MD-760P",    &radio_gd77 },      // Radioddity GD-77
+    { "MD-760",     &radio_gd77_old },  // Radioddity GD-77, older versions up to 2.6.6
     { 0, 0 }
 };
 
@@ -202,6 +203,8 @@ void radio_read_image(const char *filename)
             device = &radio_rd5r;
         } else if (memcmp(ident, "MD-760P", 7) == 0) {
             device = &radio_gd77;
+        } else if (memcmp(ident, "MD-760", 6) == 0) {
+            device = &radio_gd77_old;
         } else {
             fprintf(stderr, "%s: Unrecognized header '%.6s'\n",
                 filename, ident);
diff --git a/radio.h b/radio.h
index 95eb5f4..43d9b84 100644
--- a/radio.h
+++ b/radio.h
@@ -124,6 +124,7 @@ extern radio_device_t radio_dp880;      // Zastone DP880
 extern radio_device_t radio_rt27d;      // Radtel RT-27D
 extern radio_device_t radio_rd5r;       // Baofeng RD-5R
 extern radio_device_t radio_gd77;       // Radioddity GD-77
+extern radio_device_t radio_gd77_old;   // Radioddity GD-77, older versions up to 2.6.6
 
 //
 // Radio: memory contents.
diff --git a/rd5r.c b/rd5r.c
index a0d4895..53ed155 100644
--- a/rd5r.c
+++ b/rd5r.c
@@ -406,12 +406,14 @@ static int rd5r_is_compatible(radio_device_t *radio)
     return strncmp("BF-5R", (char*)&radio_mem[0], 5) == 0;
 }
 
-//
-// Check whether the memory image is compatible with this device.
-//
 static int gd77_is_compatible(radio_device_t *radio)
 {
-    return strncmp("MD-760P", (char*)&radio_mem[0], 7) == 0;
+    return strncmp("MD-760", (char*)&radio_mem[0], 7) == 0;
+}
+
+static int gd77old_is_compatible(radio_device_t *radio)
+{
+    return strncmp("MD-760", (char*)&radio_mem[0], 6) == 0;
 }
 
 //
@@ -2278,3 +2280,22 @@ radio_device_t radio_gd77 = {
     rd5r_parse_row,
     rd5r_update_timestamp,
 };
+
+//
+// Radioddity GD-77, older versions up to 2.6.6
+//
+radio_device_t radio_gd77_old = {
+    "Radioddity GD-77 (old)",
+    gd77_download,
+    rd5r_upload,
+    gd77old_is_compatible,
+    rd5r_read_image,
+    rd5r_save_image,
+    rd5r_print_version,
+    rd5r_print_config,
+    rd5r_verify_config,
+    rd5r_parse_parameter,
+    rd5r_parse_header,
+    rd5r_parse_row,
+    rd5r_update_timestamp,
+};
diff --git a/util.c b/util.c
index 7e45830..3566c4d 100644
--- a/util.c
+++ b/util.c
@@ -256,7 +256,7 @@ void print_ascii(FILE *out, const unsigned char *text, unsigned nchars, int fill
         ch = *text++;
         if (ch == '\t')
             ch = ' ';
-        if (nchars <= 16 && ch == ' ')
+        if (fill_flag && ch == ' ')
             ch = '_';
         putc(ch, out);
     }