diff -up hplip-2.7.12/prnt/hpijs/compression.cpp.alloc hplip-2.7.12/prnt/hpijs/compression.cpp
--- hplip-2.7.12/prnt/hpijs/compression.cpp.alloc	2008-01-25 12:16:45.000000000 +0000
+++ hplip-2.7.12/prnt/hpijs/compression.cpp	2008-01-25 12:18:02.000000000 +0000
@@ -104,12 +104,12 @@ Mode9::Mode9 (SystemServices* pSys,unsig
     if (constructor_error != NO_ERROR)  // if error in base constructor
         return;
 
-	// In the worst case, compression expands data by 50%
-	compressBuf = (BYTE*)pSS->AllocMem(RasterSize + RasterSize/2);
+	// In the worst case, compression expands data by 100%
+	compressBuf = (BYTE*)pSS->AllocMem(2 * RasterSize);
 	if (compressBuf == NULL)
 		constructor_error=ALLOCMEM_ERROR;
 
-	memset(compressBuf, 0, RasterSize + RasterSize/2);
+	memset(compressBuf, 0, 2 * RasterSize);
     memset(SeedRow,0,RasterSize);
 
 	ResetSeedRow = FALSE;
@@ -199,7 +199,7 @@ BOOL Mode9::Process(RASTERDATA* input)
 		return TRUE;
 	}
 
-	memset(compressBuf, 0, inputsize + inputsize/2);
+	memset(compressBuf, 0, 2 * inputsize);
 
     unsigned int originalsize=input->rastersize[myplane];
 	unsigned int size=input->rastersize[myplane];
@@ -571,7 +571,7 @@ Mode3::Mode3 (SystemServices* pSys, Prin
     // Worst case is when two rows are completely different
     // In that case, one command byte is added for every 8 bytes
 		// In the worst case, compression expands data by 50%
-	compressBuf = (BYTE*)pSS->AllocMem(RasterSize + RasterSize/2);
+	compressBuf = (BYTE*)pSS->AllocMem(2 * RasterSize);
 	if (compressBuf == NULL)
 		constructor_error=ALLOCMEM_ERROR;