diff --git a/backend/aztec.c b/backend/aztec.c
index f503c20a..3917885e 100644
--- a/backend/aztec.c
+++ b/backend/aztec.c
@@ -672,7 +672,7 @@ int aztec(struct zint_symbol *symbol, unsigned char source[])
 	
 	ecc_level = symbol->option_1;
 	
-	if(ecc_level == -1) {
+	if((ecc_level == -1) || (ecc_level == 0)) {
 		ecc_level = 2;
 	}
 	
@@ -685,6 +685,7 @@ int aztec(struct zint_symbol *symbol, unsigned char source[])
 			/* Decide what size symbol to use - the smallest that fits the data */
 			compact = 0; /* 1 = Aztec Compact, 0 = Normal Aztec */
 			layers = 0;
+
 			switch(ecc_level) {
 				/* For each level of error correction work out the smallest symbol which
 				the data will fit in */
diff --git a/backend/composite.c b/backend/composite.c
index 7c0268ae..5e0ec9b2 100644
--- a/backend/composite.c
+++ b/backend/composite.c
@@ -1761,6 +1761,8 @@ int composite(struct zint_symbol *symbol, unsigned char source[])
 		return error_number;
 	}
 	
+	if(cc_mode < 1 || cc_mode > 3) { cc_mode = 1; }
+
 	if(cc_mode == 1) {
 		i = cc_binary_string(symbol, reduced, binary_string, cc_mode, &cc_width, &ecc_level, linear->width);
 		if (i == ERROR_TOO_LONG) {
diff --git a/backend/library.c b/backend/library.c
index a3b40713..f59af0fe 100644
--- a/backend/library.c
+++ b/backend/library.c
@@ -430,7 +430,7 @@ int ZBarcode_Encode(struct zint_symbol *symbol, unsigned char *source)
 	if((symbol->symbology >= 112) && (symbol->symbology <= 127)) { strcpy(symbol->errtxt, "Symbology out of range, using Code 128 [Z10]"); symbol->symbology = BARCODE_CODE128; error_number = WARN_INVALID_OPTION; }
 	/* Everything from 128 up is Zint-specific */
 	if(symbol->symbology >= 140) { strcpy(symbol->errtxt, "Symbology out of range, using Code 128 [Z11]"); symbol->symbology = BARCODE_CODE128; error_number = WARN_INVALID_OPTION; }
-
+	
 	if(error_number > 4) {
 		error_tag(symbol->errtxt, error_number);
 		return error_number;
diff --git a/backend/micqr.c b/backend/micqr.c
index b7e59977..9c2a0a20 100644
--- a/backend/micqr.c
+++ b/backend/micqr.c
@@ -2,7 +2,7 @@
 
 /*
     libzint - the open source barcode library
-    Copyright (C) 2008 Robin Stuart <robin@zint.org.uk>
+    Copyright (C) 2009 Robin Stuart <robin@zint.org.uk>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -713,6 +713,12 @@ int microqr(struct zint_symbol *symbol, unsigned char source[])
 		return ERROR_TOO_LONG;
 	}
 	
+	symbol_size = symbol->option_2;
+	
+	if((symbol_size < 0) || (symbol_size > 4)) {
+		symbol_size = 0;
+	}
+
 	/* Decide symbol size */
 	if(symbol_size == 0) {
 		if(symbol->option_1 == 1) { /* ECC Level L */