Check for device presence

src/api/vga/mod.rs

@@ -1,10 +1,16 @@
 use crate::api::fs;
 
 pub fn graphic_mode() {
-    fs::write("/dev/vga/mode", b"320x200").ok();
+    let dev = "/dev/vga/mode";
+    if fs::is_device(dev) {
+        fs::write(dev, b"320x200").ok();
+    }
 }
 
 pub fn text_mode() {
-    fs::write("/dev/vga/mode", b"80x25").ok();
-    print!("\x1b[2J\x1b[1;1H"); // Clear screen and move to top
+    let dev = "/dev/vga/mode";
+    if fs::is_device(dev) {
+        fs::write(dev, b"80x25").ok();
+        print!("\x1b[2J\x1b[1;1H"); // Clear screen and move to top
+    }
 }

src/usr/render.rs

@@ -176,7 +176,8 @@ fn render_bmp(path: &str, config: &mut Config) -> Result<Command, ExitCode> {
                 palette[i * 3 + 1] = *g;
                 palette[i * 3 + 2] = *b;
             }
-            if fs::write("/dev/vga/palette", &palette).is_err() {
+            let dev = "/dev/vga/palette";
+            if !fs::is_device(dev) || fs::write(dev, &palette).is_err() {
                 error!("Could not set palette");
                 return Err(ExitCode::Failure);
             }