diff --git a/sys/modules/opus/fs/linkfs.lua b/sys/modules/opus/fs/linkfs.lua
index 38cceac..79ec13d 100644
--- a/sys/modules/opus/fs/linkfs.lua
+++ b/sys/modules/opus/fs/linkfs.lua
@@ -19,6 +19,9 @@ function linkfs.mount(_, source)
 		error('Source is required')
 	end
 	source = fs.combine(source, '')
+	if not fs.exists(source) then
+		error('Source is missing')
+	end
 	if fs.isDir(source) then
 		return {
 			source = source,
diff --git a/sys/modules/opus/ui/canvas.lua b/sys/modules/opus/ui/canvas.lua
index 260ad89..75e1792 100644
--- a/sys/modules/opus/ui/canvas.lua
+++ b/sys/modules/opus/ui/canvas.lua
@@ -152,7 +152,7 @@ function Canvas:write(x, y, text, bg, fg)
 		bg = _rep(self.palette[bg], #text)
 	end
 	if fg then
-		fg = _rep(self.palette[fg], #text)
+		fg = _rep(self.palette[fg] or self.palette[1], #text)
 	end
 	self:blit(x, y, text, bg, fg)
 end