diff --git a/keyboards/kprepublic/bm40hsrgb/rev2/keyboard.json b/keyboards/kprepublic/bm40hsrgb/rev2/keyboard.json
index cfaabd5c9ef..525a6088ed3 100644
--- a/keyboards/kprepublic/bm40hsrgb/rev2/keyboard.json
+++ b/keyboards/kprepublic/bm40hsrgb/rev2/keyboard.json
@@ -14,6 +14,9 @@
         "command": false,
         "nkro": false
     },
+    "build": {
+        "lto": true
+    },
     "usb": {
         "vid": "0x4B50",
         "pid": "0x3430",
diff --git a/keyboards/merge/um80/keyboard.json b/keyboards/merge/um80/keyboard.json
index 5a369877f88..1cbac749f7b 100644
--- a/keyboards/merge/um80/keyboard.json
+++ b/keyboards/merge/um80/keyboard.json
@@ -42,6 +42,9 @@
         "sleep": true,
         "split_count": [48, 52]
     },
+    "build": {
+        "lto": true
+    },
     "processor": "atmega32u4",
     "bootloader": "atmel-dfu",
     "layouts": {