diff --git a/hdrcache.c b/hdrcache.c
index 5bcef1a..b0e16bc 100644
--- a/hdrcache.c
+++ b/hdrcache.c
@@ -95,6 +95,15 @@ int make_key(const char *path, const struct stat *st, char *key)
 static
 const int hdrsize_max = (256 << 10);
 
+static
+unsigned hash(const unsigned char *blob, int size)
+{
+    unsigned h = 5381;
+    while (size-- > 0)
+	h = h * 33 + *blob++;
+    return h;
+}
+
 Header hdrcache_get(const char *path, const struct stat *st, unsigned *off)
 {
     if (initialize() < 0)
@@ -117,9 +126,9 @@ Header hdrcache_get(const char *path, const struct stat *st, unsigned *off)
 	mcdb_put(env, key, keysize, data, datasize);
     }
     void *blob = data->blob;
+    int blobsize = datasize - sizeof(struct cache_ent) + 1;
     char ublob[hdrsize_max];
     if (data->vflags & V_LZO) {
-	int blobsize = datasize - sizeof(struct cache_ent) + 1;
 	lzo_uint ublobsize = 0;
 	int rc = lzo1x_decompress(blob, blobsize, ublob, &ublobsize, NULL);
 	if (rc != LZO_E_OK || ublobsize < 1 || ublobsize > hdrsize_max) {
@@ -127,8 +136,11 @@ Header hdrcache_get(const char *path, const struct stat *st, unsigned *off)
 	    return NULL;
 	}
 	blob = ublob;
+	blobsize = ublobsize;
     }
+    fprintf(stderr, "blob %x (%d) hash 1: %x\n", *(unsigned *) blob, blobsize, hash(blob, blobsize));
     Header h = headerLoad(blob);
+    fprintf(stderr, "blob %x (%d) hash 2: %x\n", *(unsigned *) blob, blobsize, hash(blob, blobsize));
     if (h == NULL) {
 	fprintf(stderr, "%s %s: headerLoad failed\n", __func__, key);
 	return NULL;