diff --git a/cgdoom/cgdoom-ui.c b/cgdoom/cgdoom-ui.c
index 019b05e..d71100f 100644
--- a/cgdoom/cgdoom-ui.c
+++ b/cgdoom/cgdoom-ui.c
@@ -54,7 +54,8 @@ static uint32_t const font_glyphs[263] = {
 
 static inline void SetPixel(int x, int y, int color)
 {
-	VRAM[WIDTH * y + x] = color;
+	if ((unsigned)x < 384 && (unsigned)y < 216)
+		VRAM[WIDTH * y + x] = color;
 }
 
 static void Font_RenderChar(int *x, int y, int c, int fg)
@@ -96,22 +97,41 @@ static int Font_StringLength(char const *text)
 	return w - 1;
 }
 
-void UI_Print(int x, int y, int fg, int align, char const *text)
+static int Font_ReverseStringLength(char const *text, int width)
+{
+	int i = 0;
+	for(; text[i]; i++) {
+		if(text[i] < 32)
+			continue;
+
+		int cw = font_width[text[i]-32] + 1;
+		if(cw > width)
+			break;
+
+		width -= cw;
+	}
+	return i;
+}
+
+void UI_Print(int x, int y, int fg, int align, char const *text, int length)
 {
 	if(align == UI_CENTER)
 		x -= (Font_StringLength(text) + 1) / 2;
 	if(align == UI_RIGHT)
 		x -= Font_StringLength(text);
 
-	for(int i = 0; text[i]; i++)
+	for(int i = 0; text[i]; i++) {
+		if (length >= 0 && i >= length)
+			break;
 		Font_RenderChar(&x, y, text[i], fg);
+	}
 }
 
 void UI_Vprintf(int x, int y, int fg, int align, char const *fmt, va_list args)
 {
 	char str[256];
-	vsprintf(str, fmt, args);
-	UI_Print(x, y, fg, align, str);
+	vsnprintf(str, 256, fmt, args);
+	UI_Print(x, y, fg, align, str, -1);
 }
 
 void UI_Printf(int x, int y, int fg, int align, char const *fmt, ...)
@@ -237,7 +257,7 @@ static void Layout_EndInput(Layout *l)
 
 void Layout_CenteredText(Layout *l, const char *text)
 {
-	UI_Print(WIDTH / 2, l->y, 0x0000, UI_CENTER, text);
+	UI_Print(WIDTH / 2, l->y, 0x0000, UI_CENTER, text, -1);
 	l->y += 14;
 }
 
@@ -246,7 +266,7 @@ void Layout_Text(Layout *l, const char *label, const char *fmt, ...)
 	va_list args;
 	va_start(args, fmt);
 	Layout_AddFocus(l, FOCUS_NOTHING, NULL);
-	UI_Print(LAYOUT_LEFT, l->y, 0x0000, UI_LEFT, label);
+	UI_Print(LAYOUT_LEFT, l->y, 0x0000, UI_LEFT, label, -1);
 	UI_Vprintf(LAYOUT_RIGHT, l->y, 0x0000, UI_RIGHT, fmt, args);
 	l->y += 14;
 	va_end(args);
@@ -255,7 +275,7 @@ void Layout_Text(Layout *l, const char *label, const char *fmt, ...)
 void Layout_Checkbox(Layout *l, const char *label, int *checked)
 {
 	Layout_AddFocus(l, FOCUS_CHECKBOX, checked);
-	UI_Print(LAYOUT_LEFT, l->y, 0x0000, UI_LEFT, label);
+	UI_Print(LAYOUT_LEFT, l->y, 0x0000, UI_LEFT, label, -1);
 	UI_Checkbox(LAYOUT_RIGHT-7, l->y+1, *checked);
 	l->y += 14;
 }
@@ -263,9 +283,9 @@ void Layout_Checkbox(Layout *l, const char *label, int *checked)
 void Layout_Integer(Layout *l, const char *label, int *value)
 {
 	Layout_AddFocus(l, FOCUS_INTEGER, value);
-	UI_Print(LAYOUT_LEFT, l->y, 0x0000, UI_LEFT, label);
+	UI_Print(LAYOUT_LEFT, l->y, 0x0000, UI_LEFT, label, -1);
 	if(l->active && l->focus == l->focus_count - 1)
-		UI_Print(LAYOUT_RIGHT, l->y, 0x0000, UI_RIGHT, l->text);
+		UI_Print(LAYOUT_RIGHT, l->y, 0x0000, UI_RIGHT, l->text, -1);
 	else
 		UI_Printf(LAYOUT_RIGHT, l->y, 0x0000, UI_RIGHT, "%d", *value);
 	l->y += 14;
@@ -427,3 +447,42 @@ int UI_Main(WADFileInfo *wads, int wad_count, int *dev_info, int *use_mmap,
 
 	return -1;
 }
+
+static int isspace_(int c)
+{
+	return (c == ' ' || c == '\t' || c == '\n');
+}
+
+void UI_Error(const char *fmt, va_list args)
+{
+	char message[256], *str=message;
+	vsnprintf(message, 256, fmt, args);
+
+	int y = 12;
+	Bdisp_AllClr_VRAM();
+	UI_Print(192, y, 0x0000, UI_CENTER, "Error!", -1);
+	y += 14 + 12;
+
+	while(*str) {
+		int len = Font_ReverseStringLength(str, LAYOUT_RIGHT - LAYOUT_LEFT);
+
+		/* Try to stop at previous word boundary */
+		int wordb = len;
+		while(wordb > 0 && str[wordb] && !isspace_(str[wordb])) wordb--;
+		if(wordb > 0) len = wordb;
+
+		UI_Print(LAYOUT_LEFT, y, 0x0000, UI_LEFT, str, len);
+		y += 14;
+
+		/* Skip spacing */
+		str += len;
+		while(*str && isspace_(*str)) str++;
+	}
+
+	Bdisp_FrameAndColor(3, 16);
+	Bdisp_FrameAndColor(1, 0);
+	Bdisp_PutDisp_DD();
+
+	int key;
+	GetKey(&key);
+}
diff --git a/cgdoom/cgdoom-ui.h b/cgdoom/cgdoom-ui.h
index 060492c..5b0e0a4 100644
--- a/cgdoom/cgdoom-ui.h
+++ b/cgdoom/cgdoom-ui.h
@@ -18,7 +18,7 @@ enum {
 void UI_FileMappingProgressBar(int size_mapped, int size_total);
 
 /* Print text with a cleaner font. */
-void UI_Print(int x, int y, int fg, int halign, char const *text);
+void UI_Print(int x, int y, int fg, int halign, char const *text, int length);
 /* Like UI_Print, but applies printf() formatting. */
 void UI_Printf(int x, int y, int fg, int halign, char const *fmt, ...);
 void UI_Vprintf(int x, int y, int fg, int halign, char const *fmt, va_list args);
@@ -72,4 +72,7 @@ int UI_Main(WADFileInfo *wads, int wad_count,
     int *enabledemos      /* Enable demos on the title screen */
 );
 
+/* Show an error with custom formatting. */
+void UI_Error(const char *fmt, va_list args);
+
 #endif /* CGDOOM_UI_H */
diff --git a/cgdoom/cgdoom.c b/cgdoom/cgdoom.c
index 98a2754..d88fa3b 100644
--- a/cgdoom/cgdoom.c
+++ b/cgdoom/cgdoom.c
@@ -594,7 +594,8 @@ int Flash_ReadFile(void *buf, int size, int readpos)
 	{
 		int i = FindInFlash(&pSrc,size, readpos);
 		if(i<0) {
-			I_ErrorI ("Flash_ReadFile", size, readpos, 0, i);
+			I_Error ("Flash_ReadFile: cannot find position %d (size %d)", readpos,
+				size);
 			return i;
 		}
 		memcpy(buf,pSrc,i);
diff --git a/cgdoom/i_system.c b/cgdoom/i_system.c
index 33821c0..cc938ca 100644
--- a/cgdoom/i_system.c
+++ b/cgdoom/i_system.c
@@ -25,6 +25,7 @@
 #include "platform.h"
 #include "cgdoom.h"
 #include "cgdoom-alloc.h"
+#include "cgdoom-ui.h"
 #include <stdlib.h>
 
 #include "doomdef.h"
@@ -195,52 +196,21 @@ int toupper_int(int i)
 //
 // I_Error
 //
-static int key = 31;
-void I_ErrorI (const char *error, int i1,int i2,int i3,int i4)
-{
-  #ifndef CG_EMULATOR
-
-    char buf[21];
-    Bdisp_AllClr_VRAM();
-    locate_OS( 1, 1 );
-    PrintLine( "ERROR:", 21 );
-    locate_OS( 1, 2 );
-    PrintLine( error, 21 );
-    locate_OS( 1, 3 );CGDAppendHex32("i1:",i1,8,buf);PrintLine( buf, 21 );
-    locate_OS( 1, 4 );CGDAppendHex32("i2:",i2,8,buf);PrintLine( buf, 21 );
-    locate_OS( 1, 5 );CGDAppendHex32("i3:",i3,8,buf);PrintLine( buf, 21 );
-    locate_OS( 1, 6 );CGDAppendHex32("i4:",i4,8,buf);PrintLine( buf, 21 );
-    GetKey( &key );
-    I_ReinitAfterError();
-#else
-      I_Error (error,i1,i2,i3,i4);
-#endif
-}
-
 void I_Error (const char *error, ...)
 {
+    va_list args;
+    va_start(args, error);
+
 #ifdef CG_EMULATOR
-    /*// Message first.
-    va_start (argptr,error);
-    printf ("Error: ");
-    printf (error,argptr);
-    printf ("\n");
-    sprintf(ferror,error,argptr);
-    va_end (argptr);
-    */
-    printf ("Error: %s",error);
-    //Inform the user something bad had occured
-    //Exit function here
+    printf("Error: ");
+    vprintf(error, args);
 #else
-  I_ShutdownGraphics();
-    Bdisp_AllClr_VRAM();
-    locate_OS( 1, 1 );
-    PrintLine( "ERROR:", 21 );
-    locate_OS( 1, 2 );
-    PrintLine( error, 21 );
-    GetKey( &key );
+    I_ShutdownGraphics();
+    UI_Error(error, args);
     I_ReinitAfterError();
-#endif //#ifdef CG_EMULATOR
+#endif
+
+    va_end(args);
     //I_Quit();
 }
 
diff --git a/cgdoom/i_system.h b/cgdoom/i_system.h
index 8f5a294..8f368e5 100644
--- a/cgdoom/i_system.h
+++ b/cgdoom/i_system.h
@@ -94,9 +94,6 @@ int  	toupper_int(int i);
 //void	I_GetMainDir(char* dir);
 void 	I_Error (const char *error, ...);
 
-//CGD bastl/hack
-void I_ErrorI (const char *error, int i1,int i2,int i3,int i4);
-
 //Set by I_Error()
 extern boolean fuck;
 
diff --git a/cgdoom/i_video.c b/cgdoom/i_video.c
index b343982..164a6b6 100644
--- a/cgdoom/i_video.c
+++ b/cgdoom/i_video.c
@@ -215,6 +215,10 @@ void I_ReinitAfterError(void)
     /* Redraw status bar over help message */
     extern boolean st_firsttime;
     st_firsttime = true;
+
+    /* Restore full black screen */
+    memset(GetVRAMAddress(), 0, 384*216*2);
+    Bdisp_PutDisp_DD();
 }
 
 #endif
diff --git a/cgdoom/os.h b/cgdoom/os.h
index 53fbf83..ebf1688 100644
--- a/cgdoom/os.h
+++ b/cgdoom/os.h
@@ -31,7 +31,6 @@ void CGDAppendHex32(const char *pszText,int iNum, int iDigits,char *pszBuf);
 int abs(int x);
 
 void I_Error (const char *error, ...);
-void I_ErrorI(const char *str, int i1, int i2, int i3, int i4);
 
 //force compiler error on use following:
 #define strcpy 12
diff --git a/cgdoom/w_wad.c b/cgdoom/w_wad.c
index 9945c26..9d47339 100644
--- a/cgdoom/w_wad.c
+++ b/cgdoom/w_wad.c
@@ -124,7 +124,8 @@ static int W_AddFile ()
   }
 
   if (!lumpinfo)
-    I_ErrorI ("CGDrealloc lumpinfo", (int)lumpinfo, numlumps, numlumps*sizeof(lumpinfo_t), 0);
+    I_Error ("CGDrealloc(lumpinfo) failed (%d lumps, %d bytes)", numlumps,
+      numlumps * sizeof(lumpinfo_t));
 
   lump_p = &lumpinfo[startlump];
 
@@ -293,7 +294,7 @@ void W_ReadLump(int lump, void* dest )
 
   if (c < l->size)
   {
-    I_ErrorI ("W_ReadLump: only read %i of %i on lump %i", c,l->size,lump,0);//CGD HACK
+    I_Error ("W_ReadLump: only read %i of %i on lump %i", c,l->size,lump);
   }
 }
 
@@ -373,7 +374,8 @@ static void* W_CacheLumpNumCommon( int lump, int tag,int iEnableFlash)
   }
 
   if(lumpcache[lump] == NULL)
-    I_ErrorI("W_CacheLumpNumCommon", (int)lumpcache[lump], lump, 0, 0);
+    I_Error ("W_CacheLumpNumCommon: Loading lump %d failed (%p)", lump,
+      lumpcache[lump]);
 
   return lumpcache[lump];
 }
diff --git a/cgdoom/z_zone.c b/cgdoom/z_zone.c
index 2f34815..ec92662 100644
--- a/cgdoom/z_zone.c
+++ b/cgdoom/z_zone.c
@@ -142,7 +142,7 @@ void Z_Free (const void* ptr)
   memblock_t* block;
   memblock_t* other;
 
-  if (PTR_TO_FLASH(ptr))
+  if (PTR_TO_FLASH(ptr) || ptr == NULL)
     return;
 
   memzone_t* zone = NULL;
@@ -156,7 +156,7 @@ void Z_Free (const void* ptr)
   }
   if (zone == NULL)
   {
-    I_ErrorI ("Z_Free: Out of zone", (int)ptr, 0, 0, 0);
+    I_Error ("Z_Free: %p is out of zone", ptr);
     return;
   }
 
@@ -314,7 +314,7 @@ void* Z_Malloc( int size,  int  tag,  void* user )
     {
       if (zone_no == zone_count - 1)
       {
-        I_ErrorI ("Z_Malloc failure", size, 0, 0, 0);
+        I_Error ("Z_Malloc(%d) failure", size);
         prof_leave(CGD_Perf.DynamicAllocation);
         return NULL;
       }
@@ -461,16 +461,15 @@ void Z_CheckHeap (void)
 void Z_ChangeTag2(const void* ptr,int tag )
 {
   memblock_t* block;
-  if(PTR_TO_FLASH(ptr))
-  {
+
+  if(PTR_TO_FLASH(ptr) || ptr == NULL)
     return;
-  }
 
   block = (memblock_t *) ( (byte *)ptr - sizeof(memblock_t));
 
   if (block->id != ZONEID)
   {
-    I_ErrorI ("Z_ChangeTag: freed a pointer without ZONEID", (int)ptr, 0, 0, 0);
+    I_Error ("Z_ChangeTag: freed a pointer without ZONEID: %p", ptr);
   }
 
   if (tag >= PU_PURGELEVEL && (unsigned)block->user < 0x100)