diff --git a/CHANGELOG.md b/CHANGELOG.md
index 168bd34f..a9e5a074 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,11 @@
 
 ## Fixed
 
+- Web UI
+  - `/counters.json` rejects physical port 1 on 9-port devices.
+    A mapped logical port of `0` was treated as invalid,
+    but it is a valid port there.
+
 ## Breaking changes
 
 - Config
diff --git a/httpd/page_impl.c b/httpd/page_impl.c
index b99f0b9b..e0377203 100644
--- a/httpd/page_impl.c
+++ b/httpd/page_impl.c
@@ -302,7 +302,7 @@ bool send_counters(uint8_t phys_port)
 	if (phys_port_idx > 8)
 		goto err;
 	uint8_t log_port = machine.phys_to_log_port[phys_port_idx];
-	if (log_port == 0)
+	if (log_port < machine.min_port || log_port > machine.max_port)
 		goto err;
 
 	dbg_string("send_counters called: "); dbg_byte(phys_port_idx); dbg_char('\n');