diff --git a/NitroPaint/ncgr.c b/NitroPaint/ncgr.c
index b5d2308..0f5f474 100644
--- a/NitroPaint/ncgr.c
+++ b/NitroPaint/ncgr.c
@@ -87,49 +87,21 @@ int ChrIsValidNcg(const unsigned char *buffer, unsigned int size) {
 }
 
 static int ChriIsCommonScanFooter(const unsigned char *buffer, unsigned int size, int type) {
-	if (size < 8) return -1;
+	//scan for footer with these required blocks
+	const char *const requiredBlocks[] = { "LINK", "CMNT", "MODE", "SIZE", "VER ", "END " };
+	int offs = IscadScanFooter(buffer, size, requiredBlocks, sizeof(requiredBlocks) / sizeof(requiredBlocks[0]));
+	if (offs == -1) return -1;
 
-	//scan for possible locations of the footer
-	for (unsigned int i = 0; i < size - 8; i++) {
-		if (buffer[i] != 'L') continue;
-		if (memcmp(buffer + i, "LINK", 4) != 0) continue;
-		
-		//candidate location
-		int hasLink = 0, hasCmnt = 0, hasMode = 0, hasSize = 0, hasVer = 0, hasEnd = 0;
+	unsigned int footerSize = size - (unsigned int) offs;
+	const unsigned char *footer = buffer + offs;
 
-		//scan sections
-		unsigned int offset = i;
-		while (1) {
-			const unsigned char *section = buffer + offset;
-			unsigned int length = *(uint32_t *) (buffer + offset + 4);
-			offset += 8;
+	//check blocks
+	unsigned int verSize;
+	const unsigned char *verBlock = IscadFindBlockBySignature(footer, footerSize, "VER ", &verSize);
 
-			if (memcmp(section, "LINK", 4) == 0) hasLink = 1;
-			else if (memcmp(section, "CMNT", 4) == 0) hasCmnt = 1;
-			else if (memcmp(section, "MODE", 4) == 0) hasMode = 1;
-			else if (memcmp(section, "SIZE", 4) == 0) hasSize = 1;
-			else if (memcmp(section, "VER ", 4) == 0) hasVer = 1;
-			else if (memcmp(section, "END ", 4) == 0) hasEnd = 1;
-
-			if (memcmp(section, "VER ", 4) == 0) {
-				//ACG: ver = "IS-ACG0x" (1-3)
-				//ICG: ver = "IS-ICG01"
-				const char *ver = section + 8;
-				if (type == NCGR_TYPE_AC && (length < 8 || memcmp(ver, "IS-ACG", 6))) return -1;
-				if (type == NCGR_TYPE_IC && (length < 8 || memcmp(ver, "IS-ICG", 6))) return -1;
-			}
-
-			offset += length;
-			if (offset >= size) break;
-			if (hasEnd) break;
-		}
-
-		if (hasLink && hasCmnt && hasMode && hasSize && hasVer && hasEnd && offset <= size) {
-			//candidate found
-			return i;
-		}
-	}
-	return -1;
+	if (type == NCGR_TYPE_AC && (verSize < 8 || memcmp(verBlock, "IS-ACG", 6))) return -1; // ASC must have version IS-ACGxx
+	if (type == NCGR_TYPE_IC && (verSize < 8 || memcmp(verBlock, "IS-ICG", 6))) return -1; // ISC must have version IS-ICGxx
+	return offs;
 }
 
 int ChrIsValidAcg(const unsigned char *buffer, unsigned int size) {
diff --git a/NitroPaint/nns.c b/NitroPaint/nns.c
index 8e7a887..5f917f4 100644
--- a/NitroPaint/nns.c
+++ b/NitroPaint/nns.c
@@ -709,6 +709,9 @@ int IscadIsValidFooter(const unsigned char *footer, unsigned int size) {
 		if ((size - pos) < blockSize) return 0;
 
 		pos += blockSize;
+
+		//check for 'END ' signature
+		if (memcmp(hdr, "END ", 4) == 0) break;
 	}
 	return 1;
 }
@@ -728,10 +731,40 @@ unsigned char *IscadFindBlockBySignature(const unsigned char *buffer, unsigned i
 		pos += 8;
 		unsigned int blockSize = *(const uint32_t *) (hdr + 4);
 		pos += blockSize;
+
+		//check for 'END ' signature
+		if (memcmp(hdr, "END ", 4) == 0) break;
 	}
 	return NULL;
 }
 
+int IscadScanFooter(const unsigned char *buffer, unsigned int size, const char *const *requiredBlocks, unsigned int nRequiredBlocks) {
+	//scan for locations, check for required blocks.
+	for (unsigned int i = 0; i < size; i++) {
+		//check valid footer data
+		if (!IscadIsValidFooter(buffer + i, size - i)) continue;
+
+		//check required blocks
+		int foundAll = 1;
+		for (unsigned int j = 0; j < nRequiredBlocks; j++) {
+			unsigned int blockSize;
+			const unsigned char *block = IscadFindBlockBySignature(buffer + i, size - i, requiredBlocks[j], &blockSize);
+			if (block == NULL) {
+				foundAll = 0;
+				break;
+			}
+		}
+
+		//buffer here
+		if (foundAll) {
+			return (int) i;
+		}
+	}
+
+	//not found
+	return -1;
+}
+
 
 void IscadStreamCreate(IscadStream *stream) {
 	stream->inFooter = 0;
@@ -747,7 +780,7 @@ void IscadStreamStartBlock(IscadStream *stream, const char *signature) {
 	stream->blockStart = stream->stream.pos;
 
 	uint32_t tmpSize = 0;
-	bstreamWrite(&stream->stream, signature, 4);
+	bstreamWrite(&stream->stream, (void *) signature, 4);
 	bstreamWrite(&stream->stream, &tmpSize, sizeof(tmpSize));
 }
 
diff --git a/NitroPaint/nns.h b/NitroPaint/nns.h
index 71dc157..92df735 100644
--- a/NitroPaint/nns.h
+++ b/NitroPaint/nns.h
@@ -74,6 +74,7 @@ void NnsStreamFree(NnsStream *stream);
 
 // ----- ISCAD stream functions
 
+int IscadScanFooter(const unsigned char *buffer, unsigned int size, const char *const *requiredBlocks, unsigned int nRequiredBlocks);
 int IscadIsValidFooter(const unsigned char *footer, unsigned int size);
 unsigned char *IscadFindBlockBySignature(const unsigned char *buffer, unsigned int size, const char *signature, unsigned int *pSize);
 
diff --git a/NitroPaint/nscr.c b/NitroPaint/nscr.c
index 9fea478..f475bdb 100644
--- a/NitroPaint/nscr.c
+++ b/NitroPaint/nscr.c
@@ -210,53 +210,23 @@ int ScrIsValidNsc(const unsigned char *buffer, unsigned int size) {
 }
 
 int ScriIsCommonScanFooter(const unsigned char *buffer, unsigned int size, int type) {
-	if (size < 8) return -1;
+	//scan for a footer with the required blocks
+	const char *requiredBlocks[] = { "CLRF", "LINK", "CMNT", "CLRC", "MODE", "VER ", "END " };
+	int offs = IscadScanFooter(buffer, size, requiredBlocks, sizeof(requiredBlocks) / sizeof(requiredBlocks[0]));
+	if (offs == -1) return -1;
 
-	//scan for possible locations of the footer
-	for (unsigned int i = 0; i < size - 8; i++) {
-		if (buffer[i] != 'C') continue;
-		if (memcmp(buffer + i, "CLRF", 4) != 0) continue;
+	unsigned int footerSize = size - (unsigned int) offs;
+	const unsigned char *footer = buffer + offs;
 
-		//candidate location
-		int hasClrf = 0, hasLink = 0, hasCmnt = 0, hasClrc = 0, hasMode = 0, hasVer = 0, hasEnd = 0, hasSize = 0;
+	//check blocks
+	unsigned int verSize, sizeSize;
+	const unsigned char *verBlock = IscadFindBlockBySignature(footer, footerSize, "VER ", &verSize);
+	const unsigned char *sizeBlock = IscadFindBlockBySignature(footer, footerSize, "SIZE", &sizeSize);
 
-		//scan sections
-		unsigned int offset = i;
-		while (1) {
-			const char *section = buffer + offset;
-			unsigned int length = *(unsigned int *) (buffer + offset + 4);
-			offset += 8;
-
-			if (memcmp(section, "CLRF", 4) == 0) hasClrf = 1;
-			else if (memcmp(section, "LINK", 4) == 0) hasLink = 1;
-			else if (memcmp(section, "CMNT", 4) == 0) hasCmnt = 1;
-			else if (memcmp(section, "CLRC", 4) == 0) hasClrc = 1;
-			else if (memcmp(section, "MODE", 4) == 0) hasMode = 1;
-			else if (memcmp(section, "SIZE", 4) == 0) hasSize = 1;
-			else if (memcmp(section, "VER ", 4) == 0) hasVer = 1;
-			else if (memcmp(section, "END ", 4) == 0) hasEnd = 1;
-
-			if (memcmp(section, "VER ", 4) == 0) {
-				//ACG: ver = "IS-ACG0x" (1-3)
-				//ICG: ver = "IS-ICG01"
-				const char *ver = section + 8;
-				if (type == NSCR_TYPE_AC && (length < 8 || memcmp(ver, "IS-ASC", 6))) return -1;
-				if (type == NSCR_TYPE_IC && (length < 8 || memcmp(ver, "IS-ISC", 6))) return -1;
-			}
-
-			offset += length;
-			if (offset >= size) break;
-			if (hasEnd) break;
-		}
-
-		//ISC files have a SIZE section, but ASC files do not
-		int sizeSatisfied = (type == NSCR_TYPE_IC && hasSize) || (type != NSCR_TYPE_IC);
-		if (hasClrf && hasLink && hasCmnt && hasClrc && hasMode && sizeSatisfied && hasVer && hasEnd && offset <= size) {
-			//candidate found
-			return i;
-		}
-	}
-	return -1;
+	if (type == NSCR_TYPE_AC && (verSize < 8 || memcmp(verBlock, "IS-ASC", 6))) return -1; // ASC must have version IS-ASCxx
+	if (type == NSCR_TYPE_IC && (verSize < 8 || memcmp(verBlock, "IS-ISC", 6))) return -1; // ISC must have version IS-ISCxx
+	if (type == NSCR_TYPE_IC && sizeBlock == NULL) return -1;                              // ISC must have a SIZE block
+	return offs;
 }
 
 int ScrIsValidAsc(const unsigned char *file, unsigned int size) {