diff --git a/validat3.cpp b/validat3.cpp
index b5dcd6d2..bd4c4f51 100644
--- a/validat3.cpp
+++ b/validat3.cpp
@@ -429,8 +429,17 @@ bool Test_RandomNumberGenerator(RandomNumberGenerator& prng, bool drain=false)
 		RandomNumberSource(prng, UINT_MAX, true, new Redirector(TheBitBucket()));
 	}
 
+	// Use a block that is zero'd to catch bad RNG's that appear [somewhat]
+	// OK due to entropy in the heap. We found Debian HURD was failing, but
+	// not that badly. For example, we would see "100000 generated bytes
+	// compressed to 98749 bytes by DEFLATE". Once we zero'd the block, the
+	// message changed to "100000 generated bytes compressed to 27 bytes by
+	// DEFLATE". Doh...
+	SecByteBlock block(NULLPTR, GENERATE_SIZE);
+	RandomNumberSource(prng, GENERATE_SIZE, new ArraySink(block, block.size()));
+
 	MeterFilter meter(new Redirector(TheBitBucket()));
-	RandomNumberSource(prng, GENERATE_SIZE, true, new Deflator(new Redirector(meter)));
+	StringSource(block, block.size(), true, new Deflator(new Redirector(meter)));
 
 	if (meter.GetTotalBytes() < GENERATE_SIZE)
 	{