diff --git a/CHANGELOG.md b/CHANGELOG.md
index e8e071b1c..2039ea9bf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ All notable changes to this project will be documented in this file.
 ## [14.5.0.3] 
 ### Added
 - Extend command `GPIO` with different display options and allowing updating of module GPIO's in one go
+- Berry `bytes.add()` now accepts 3-bytes values
 
 ### Breaking Changed
 
diff --git a/lib/libesp32/berry/src/be_byteslib.c b/lib/libesp32/berry/src/be_byteslib.c
index 1ddd027d5..d692286d9 100644
--- a/lib/libesp32/berry/src/be_byteslib.c
+++ b/lib/libesp32/berry/src/be_byteslib.c
@@ -258,6 +258,26 @@ static size_t buf_add2_be(buf_impl* attr, const uint16_t data) // append 16 bits
     return attr->len;
 }
 
+static size_t buf_add3_le(buf_impl* attr, const uint32_t data) // append 32 bits value
+{
+    if (attr->len < attr->size - 2) {     // do we have room for 4 bytes
+        attr->bufptr[attr->len++] = data;
+        attr->bufptr[attr->len++] = data >> 8;
+        attr->bufptr[attr->len++] = data >> 16;
+    }
+    return attr->len;
+}
+
+size_t buf_add3_be(buf_impl* attr, const uint32_t data) // append 32 bits value
+{
+    if (attr->len < attr->size - 2) {     // do we have room for 4 bytes
+        attr->bufptr[attr->len++] = data >> 16;
+        attr->bufptr[attr->len++] = data >> 8;
+        attr->bufptr[attr->len++] = data;
+    }
+    return attr->len;
+}
+
 static size_t buf_add4_le(buf_impl* attr, const uint32_t data) // append 32 bits value
 {
     if (attr->len < attr->size - 3) {     // do we have room for 4 bytes
@@ -838,10 +858,12 @@ static int m_add(bvm *vm)
             case -1:    /* fallback below */
             case 1:     buf_add1(&attr, v);       break;
             case 2:     buf_add2_le(&attr, v);    break;
+            case 3:     buf_add3_le(&attr, v);    break;
             case 4:     buf_add4_le(&attr, v);    break;
             case -2:    buf_add2_be(&attr, v);    break;
+            case -3:    buf_add3_be(&attr, v);    break;
             case -4:    buf_add4_be(&attr, v);    break;
-            default:    be_raise(vm, "type_error", "size must be -4, -2, -1, 0, 1, 2 or 4.");
+            default:    be_raise(vm, "type_error", "size must be between -4 and 4.");
         }
         be_pop(vm, argc - 1);
         m_write_attributes(vm, 1, &attr);  /* update attributes */
diff --git a/lib/libesp32/berry/tests/bytes.be b/lib/libesp32/berry/tests/bytes.be
index 0cdc8334b..3533acc2a 100644
--- a/lib/libesp32/berry/tests/bytes.be
+++ b/lib/libesp32/berry/tests/bytes.be
@@ -53,6 +53,11 @@ b.add(0x12345678, -2)
 assert(str(b) == "bytes('2278785678563412785678')")
 b.add(0x12345678, -4)
 assert(str(b) == "bytes('227878567856341278567812345678')")
+b.add(0xAABBCC, 3)
+assert(str(b) == "bytes('227878567856341278567812345678CCBBAA')")
+b.add(0x998877, -3)
+assert(str(b) == "bytes('227878567856341278567812345678CCBBAA998877')")
+
 
 #- get -#
 b=bytes("000102030405")