diff -r 90ad7324bbbc -r 1a9e6a5c1e79 dav/sync.c
--- a/dav/sync.c	Sun Apr 07 17:56:31 2019 +0200
+++ b/dav/sync.c	Tue Apr 09 18:19:52 2019 +0200
@@ -1087,7 +1087,7 @@
     memset(&s, 0, sizeof(SYS_STAT));
     
     char *blocksize_str = dav_get_string_property_ns(res, DAV_NS, "split");
-    int64_t blocksize = 0;
+    uint64_t blocksize = 0;
     DavBool issplit = FALSE;
     if(blocksize_str) {
         if(!util_strtouint(blocksize_str, &blocksize)) {
@@ -3146,7 +3146,7 @@
     }
     
     // set content-hash
-    char content_hash[DAV_SHA256_DIGEST_LENGTH];
+    unsigned char content_hash[DAV_SHA256_DIGEST_LENGTH];
     dav_hash_final(sha, content_hash);
     sync_set_content_hash(res, content_hash);
     local->hash = util_hexstr(content_hash, DAV_SHA256_DIGEST_LENGTH);
@@ -4585,18 +4585,18 @@
     return NULL;
 }
 
-void sync_set_content_hash(DavResource *res, const char *hashdata) {
+void sync_set_content_hash(DavResource *res, const unsigned char *hashdata) {
     uint32_t flags = res->session->flags;
     if((flags & DAV_SESSION_ENCRYPT_CONTENT) == DAV_SESSION_ENCRYPT_CONTENT) {
         if(res->session->key) {
-            char *enc_hash = aes_encrypt(hashdata, DAV_SHA256_DIGEST_LENGTH, res->session->key);
+            char *enc_hash = aes_encrypt((const char*)hashdata, DAV_SHA256_DIGEST_LENGTH, res->session->key);
             if(enc_hash) {
                 dav_set_string_property_ns(res, DAV_NS, "crypto-hash", enc_hash);
                 free(enc_hash);
             }
         }
     } else {
-        char *hex_hash = util_hexstr((const unsigned char*)hashdata, DAV_SHA256_DIGEST_LENGTH);
+        char *hex_hash = util_hexstr(hashdata, DAV_SHA256_DIGEST_LENGTH);
         dav_set_string_property_ns(res, DAV_NS, "content-hash", hex_hash);
         free(hex_hash);
     }