diff --git a/host/src/simtrace2-cardem-pcsc.c b/host/src/simtrace2-cardem-pcsc.c
index 0eaf2c3d..dabe693a 100644
--- a/host/src/simtrace2-cardem-pcsc.c
+++ b/host/src/simtrace2-cardem-pcsc.c
@@ -587,7 +587,8 @@ int main(int argc, char **argv)
 		ifm->configuration = config_id;
 		ifm->interface = if_num;
 		ifm->altsetting = altsetting;
-		ifm->addr = addr;
+		if (addr > 0 && addr < 256)
+			ifm->addr = addr;
 		if (path)
 			osmo_strlcpy(ifm->path, path, sizeof(ifm->path));
 		transp->udp_fd = -1;
diff --git a/host/src/simtrace2-tool.c b/host/src/simtrace2-tool.c
index b0fac6c1..fdf0d566 100644
--- a/host/src/simtrace2-tool.c
+++ b/host/src/simtrace2-tool.c
@@ -309,7 +309,8 @@ int main(int argc, char **argv)
 			ifm->configuration = config_id;
 			ifm->interface = if_num;
 			ifm->altsetting = altsetting;
-			ifm->addr = addr;
+			if (addr > 0 && addr < 256)
+				ifm->addr = addr;
 			if (path)
 				osmo_strlcpy(ifm->path, path, sizeof(ifm->path));
 			transp->usb_devh = osmo_libusb_open_claim_interface(NULL, NULL, ifm);