diff --git a/iop/scripts/genconfig.sh b/iop/scripts/genconfig.sh
index 6d21bb468..7a320118e 100755
--- a/iop/scripts/genconfig.sh
+++ b/iop/scripts/genconfig.sh
@@ -363,7 +363,7 @@ function genconfig {
 		airoha | iopsys_mediatek | brcmbca | ipq95xx)
 			# This assumes the device name to be unique within one target,
 			# which is a fair assumption to make.
-			local subtarget="$(get_subtarget_for_device "$target" "$BOARDTYPE")"
+			local subtarget="$(get_subtarget_for_device "${target/_/-}" "$BOARDTYPE")"
 			if [ -z "$subtarget" ]; then
 				echo "Error determining subtarget for $target / ${BOARDTYPE}"
 				return 1
diff --git a/iop/scripts/genconfig_min.sh b/iop/scripts/genconfig_min.sh
index ffc3ab6ba..6856974df 100644
--- a/iop/scripts/genconfig_min.sh
+++ b/iop/scripts/genconfig_min.sh
@@ -337,7 +337,7 @@ function genconfig_min {
 		airoha | iopsys_mediatek | brcmbca | ipq95xx)
 			# This assumes the device name to be unique within one target,
 			# which is a fair assumption to make.
-			local subtarget="$(get_subtarget_for_device "$target" "$BOARDTYPE")"
+			local subtarget="$(get_subtarget_for_device "${target/_/-}" "$BOARDTYPE")"
 			if [ -z "$subtarget" ]; then
 				echo "Error determining subtarget for $target / ${BOARDTYPE}"
 				return 1