diff --git a/ka/ABI b/ka/ABI
index 15a730c..2a4d9ef 100644
--- a/ka/ABI
+++ b/ka/ABI
@@ -109,8 +109,8 @@ To the variadic function, argN can be accessed the following way:
         mov reg, [rbp + N*8 + 16]
 
 For instance:
-        mov rax, [rbp + 16]     ; arg1
-        mov rdx, [rbp + 24]     ; arg2
+        mov rax, [rbp + 16]     ; arg0
+        mov rdx, [rbp + 24]     ; arg1
 
 It is recommended to use the reg+reg*imm16+imm16 memory format:
         mov rax, [rbp + rcx * 8 + 16]       ; accesses arg#rcx
diff --git a/vm/cn/console.c b/vm/cn/console.c
index 363a80e..2181ffd 100644
--- a/vm/cn/console.c
+++ b/vm/cn/console.c
@@ -114,6 +114,12 @@ void console_putat(ctx_t *ctx, char ch, int x, int y)
 
     surf = TTF_RenderText_Solid(scr_font, scr_lines[y], scr_text_color);
 
+    if (!surf)
+    {
+        logerr("console_putat: couldn't render TTF font\n");
+        die(-1);
+    }
+
     if (scr_texts[y])
     {
         if (scr_rects[y])
@@ -128,10 +134,18 @@ void console_putat(ctx_t *ctx, char ch, int x, int y)
     scr_texts[y] = SDL_CreateTextureFromSurface(scr_rend, surf);
     scr_rects[y] = malloc(sizeof(SDL_Rect));
 
+    if (scr_texts[y] == NULL)
+    {
+        logerr("console_putat: couldn't create texture from surface\n");
+        SDL_FreeSurface(surf);
+        die(-1);
+    }
+
     if (scr_rects[y] == NULL)
     {
         logerr("console_putat: not enough memory\n");
         SDL_FreeSurface(surf);
+        SDL_DestroyTexture(scr_texts[y]);
         die(-1);
     }