diff --git a/board/config.c b/board/config.c
index 95eeecf..19d47bc 100644
--- a/board/config.c
+++ b/board/config.c
@@ -72,6 +72,7 @@ void aime_config_load(struct aime_config *cfg, const wchar_t *filename)
 
     aime_dll_config_load(&cfg->dll, filename);
     cfg->enable = GetPrivateProfileIntW(L"aime", L"enable", 1, filename);
+    cfg->port_no = GetPrivateProfileIntW(L"aime", L"portNo", 0, filename);
     cfg->high_baudrate = GetPrivateProfileIntW(L"aime", L"highBaud", 1, filename);
     cfg->gen = GetPrivateProfileIntW(L"aime", L"gen", 0, filename);
 }
@@ -90,7 +91,7 @@ void vfd_config_load(struct vfd_config *cfg, const wchar_t *filename)
     assert(filename != NULL);
 
     cfg->enable = GetPrivateProfileIntW(L"vfd", L"enable", 1, filename);
-    cfg->port = GetPrivateProfileIntW(L"vfd", L"portNo", 0, filename);
+    cfg->port_no = GetPrivateProfileIntW(L"vfd", L"portNo", 0, filename);
     cfg->utf_conversion = GetPrivateProfileIntW(L"vfd", L"utfConversion", 0, filename);
 }
 
diff --git a/board/sg-reader.c b/board/sg-reader.c
index bcbef56..bcc9701 100644
--- a/board/sg-reader.c
+++ b/board/sg-reader.c
@@ -47,7 +47,7 @@ static struct sg_led sg_reader_led;
 
 HRESULT sg_reader_hook_init(
         const struct aime_config *cfg,
-        unsigned int port_no,
+        unsigned int default_port_no,
         unsigned int gen,
         HINSTANCE self)
 {
@@ -66,6 +66,11 @@ HRESULT sg_reader_hook_init(
         return hr;
     }
 
+    unsigned int port_no = cfg->port_no;
+    if (port_no == 0){
+        port_no = default_port_no;
+    }
+
     if (cfg->gen != 0) {
         gen = cfg->gen;
     }
@@ -85,6 +90,7 @@ HRESULT sg_reader_hook_init(
         sg_reader_uart.baud.BaudRate = 38400;
     }
 
+    dprintf("NFC Assembly: enabling (port=%d)\n", port_no);
     uart_init(&sg_reader_uart, port_no);
     sg_reader_uart.written.bytes = sg_reader_written_bytes;
     sg_reader_uart.written.nbytes = sizeof(sg_reader_written_bytes);
diff --git a/board/sg-reader.h b/board/sg-reader.h
index 01eb0b3..1824e28 100644
--- a/board/sg-reader.h
+++ b/board/sg-reader.h
@@ -9,12 +9,13 @@
 struct aime_config {
     struct aime_dll_config dll;
     bool enable;
+    unsigned int port_no;
     bool high_baudrate;
     unsigned int gen;
 };
 
 HRESULT sg_reader_hook_init(
         const struct aime_config *cfg,
-        unsigned int port_no,
+        unsigned int default_port_no,
         unsigned int gen,
         HINSTANCE self);
diff --git a/board/vfd.c b/board/vfd.c
index 34b89d4..4cfb20b 100644
--- a/board/vfd.c
+++ b/board/vfd.c
@@ -51,7 +51,7 @@ HRESULT vfd_handle_create_char2(struct const_iobuf* reader, struct iobuf* writer
 
 static bool utf_enabled;
 
-HRESULT vfd_hook_init(struct vfd_config *cfg, int default_port)
+HRESULT vfd_hook_init(struct vfd_config *cfg, unsigned int default_port_no)
 {
     if (!cfg->enable){
         return S_FALSE;
@@ -59,13 +59,13 @@ HRESULT vfd_hook_init(struct vfd_config *cfg, int default_port)
 
     utf_enabled = cfg->utf_conversion;
 
-    int port = cfg->port;
-    if (port == 0){
-        port = default_port;
+    unsigned int port_no = cfg->port_no;
+    if (port_no == 0){
+        port_no = default_port_no;
     }
 
-    dprintf("VFD: enabling (port=%d)\n", port);
-    uart_init(&vfd_uart, port);
+    dprintf("VFD: enabling (port=%d)\n", port_no);
+    uart_init(&vfd_uart, port_no);
     vfd_uart.written.bytes = vfd_written;
     vfd_uart.written.nbytes = sizeof(vfd_written);
     vfd_uart.readable.bytes = vfd_readable;
diff --git a/board/vfd.h b/board/vfd.h
index 3e67061..5d3664c 100644
--- a/board/vfd.h
+++ b/board/vfd.h
@@ -4,10 +4,10 @@
 
 struct vfd_config {
     bool enable;
-    int port;
+    unsigned int port_no;
     bool utf_conversion;
 };
 
 
-HRESULT vfd_hook_init(struct vfd_config *cfg, int default_port);
+HRESULT vfd_hook_init(struct vfd_config *cfg, unsigned int default_port_no);
 
diff --git a/doc/config/common.md b/doc/config/common.md
index db866b2..5368bec 100644
--- a/doc/config/common.md
+++ b/doc/config/common.md
@@ -42,6 +42,12 @@ Default: `1`
 Enable Aime card reader assembly emulation. Disable to use a real SEGA Aime
 reader (COM port number varies by game).
 
+### `portNo`
+
+Default: (game specific)
+
+Sets the COM port to use for the aime card reader assembly.
+
 ### `highBaud`
 
 Default: `1`