diff --git a/top/x300/yaml_include/x3xx_radio_base.yml b/top/x300/yaml_include/x3xx_radio_base.yml
index dcff223..5af8c56 100644
--- a/top/x300/yaml_include/x3xx_radio_base.yml
+++ b/top/x300/yaml_include/x3xx_radio_base.yml
@@ -67,6 +67,10 @@ connections:
   # RF A TX
   - { srcblk: ep0,    srcport: out0,  dstblk: duc0,   dstport: in_0 }
   - { srcblk: duc0,   srcport: out_0, dstblk: radio0, dstport: in_0 }
+  # This is a fake connection: It signals to the image builder that we are
+  # deliberately not connecting this port, so it doesn't have to print a warning
+  # about it.
+  - { srcblk: _device_,  srcport: _none_, dstblk: radio0, dstport: in_1 }
   # RF A RX
   - { srcblk: radio0, srcport: out_0, dstblk: ddc0,   dstport: in_0 }
   - { srcblk: ddc0,   srcport: out_0, dstblk: ep0,    dstport: in0  }
@@ -77,6 +81,8 @@ connections:
   # RF B TX
   - { srcblk: ep2,    srcport: out0,  dstblk: duc1,   dstport: in_0 }
   - { srcblk: duc1,   srcport: out_0, dstblk: radio1, dstport: in_0 }
+  # See comment above about fake connections.
+  - { srcblk: _device_,  srcport: _none_, dstblk: radio1, dstport: in_1 }
   # RF B RX
   - { srcblk: radio1, srcport: out_0, dstblk: ddc1,   dstport: in_0 }
   - { srcblk: ddc1,   srcport: out_0, dstblk: ep2,    dstport: in0  }