diff --git a/doc/jbhook/jbio-magicbox.md b/doc/jbhook/jbio-magicbox.md
index 253c07e..2bb17a5 100644
--- a/doc/jbhook/jbio-magicbox.md
+++ b/doc/jbhook/jbio-magicbox.md
@@ -2,10 +2,12 @@ This library talks to a MagicBox cab's IO and implements the jbio API of BT5.
 Thus, it allows you to use a MagicBox cab with *any* version of jubeat that is supported by BT5.
 
 # Setup
-* Rename jbio-magicbox.dll to jbio.dll.
-* Ensure that your gamestart.bat actually injects the appropriate jbhook dll
+* Rename `jbio-magicbox.dll` to `jbio.dll`.
+* Make sure `jbio.dll` is in the same folder as both `jbhook.dll` and `jubeat.dll`
+* Make sure that you have a copy of the `ch341dll.dll` that comes with MagicBox.
+* Ensure that your `gamestart.bat` actually injects the appropriate jbhook dll
 for example:
 ```
 launcher -K jbhook.dll jubeat.dll ...*
 ```
-or that the application otherwise uses jbio.dll
+or that the application otherwise uses `jbio.dll`
diff --git a/src/main/jbio-magicbox/jbio.c b/src/main/jbio-magicbox/jbio.c
index 057d5df..c156120 100644
--- a/src/main/jbio-magicbox/jbio.c
+++ b/src/main/jbio-magicbox/jbio.c
@@ -12,10 +12,15 @@ static uint8_t jb_io_sys_buttons;
 
 static bool is_initialized = false;
 
-log_formatter_t jb_io_log_misc;
-log_formatter_t jb_io_log_info;
-log_formatter_t jb_io_log_warning;
-log_formatter_t jb_io_log_fatal;
+static log_formatter_t jb_io_log_misc;
+static log_formatter_t jb_io_log_info;
+static log_formatter_t jb_io_log_warning;
+static log_formatter_t jb_io_log_fatal;
+
+union magicbox_input {
+    uint32_t dword;
+    uint8_t bytes[4];
+};
 
 void jb_io_set_loggers(
     log_formatter_t misc,
@@ -77,11 +82,8 @@ static const uint32_t magic_sys_mappings[] = {
 bool jb_io_read_inputs(void)
 {
     // Read IO board
-    unsigned long n;
-    union {
-        uint32_t dword;
-        uint8_t bytes[4];
-    } input;
+    unsigned long size;
+    union magicbox_input input;
 
     input.dword = -1;
     jb_io_panels = 0;
@@ -91,16 +93,16 @@ bool jb_io_read_inputs(void)
     CH341EppSetAddr(0, 1);
     CH341EppSetAddr(0, 255);
     CH341EppSetAddr(0, 0);
-    n = 1;
-    CH341EppReadData(0, &input.bytes[0], &n);
+    size = sizeof(uint8_t);
+    CH341EppReadData(0, &input.bytes[0], &size);
     CH341EppSetAddr(0, 255);
     CH341EppSetAddr(0, 0);
-    n = 1;
-    CH341EppReadData(0, &input.bytes[1], &n);
+    size = sizeof(uint8_t);
+    CH341EppReadData(0, &input.bytes[1], &size);
     CH341EppSetAddr(0, 255);
     CH341EppSetAddr(0, 0);
-    n = 1;
-    CH341EppReadData(0, &input.bytes[2], &n);
+    size = sizeof(uint8_t);
+    CH341EppReadData(0, &input.bytes[2], &size);
     CH341EppSetAddr(0, 255);
 
     for (uint8_t i = 0; i < lengthof(magic_panel_mappings); i++) {