diff --git a/src/common/kernel/group.c b/src/common/kernel/group.c
index e365818c9..6c266c1e7 100644
--- a/src/common/kernel/group.c
+++ b/src/common/kernel/group.c
@@ -33,6 +33,7 @@
 #include <util/unicode.h>
 
 /* libc includes */
+#include <assert.h>
 #include <stdlib.h>
 #include <string.h>
 #include <wctype.h>
@@ -216,7 +217,7 @@ read_groups(struct storage * store, faction * f)
       ally * a;
       variant fid;
       fid.i = store->r_id(store);
-      if (fid.i<0) break;
+      if (fid.i<=0) break;
       if (store->version<STORAGE_VERSION && fid.i==0) break;
       a = malloc(sizeof(ally));
       *pa = a;
diff --git a/src/common/util/base36.c b/src/common/util/base36.c
index c0eb6025f..78a213d09 100644
--- a/src/common/util/base36.c
+++ b/src/common/util/base36.c
@@ -31,11 +31,15 @@ atoi36(const char * str)
 {
   /* cannot use strtol, becuase invalid strings will cause crash */
   const unsigned char * s = (const unsigned char *)str;
-  int i = 0;
+  int i = 0, sign = 1;
   assert(s);
   if(!(*s)) return 0;
 
   while(isspace(*(unsigned char*)s)) ++s;
+  if (*s == '-') {
+    sign = -1;
+    ++s;
+  }
   while(isalnum(*(unsigned char*)s)) {
     if (isupper(*(unsigned char*)s)) i = i*36 + (*s)-'A' + 10;
     else if (islower(*(unsigned char*)s)) i=i*36 + (*s)-'a' + 10;
@@ -45,7 +49,7 @@ atoi36(const char * str)
     ++s;
   }
   if (i<0) return 0;
-  return i;
+  return i * sign;
 }
 
 const char*
diff --git a/src/scripts/run-tests.lua b/src/scripts/run-tests.lua
index 70629a5c2..a2fc96061 100644
--- a/src/scripts/run-tests.lua
+++ b/src/scripts/run-tests.lua
@@ -12,14 +12,15 @@ end
 test_locales()
 
 local now = os.clock()
-read_game("566.dat", "binary")
---read_game("566", "text")
+--read_game("566.dat", "binary")
+read_game("566.txt", "text")
+--write_game("566.txt", "text")
 local elapsed = os.clock() - now
 print(elapsed)
 -- text: 50.574
 -- bin0: 19.547
 -- bin1: 18.953
 
-write_game("566.dat", "binary")
+--write_game("566.dat", "binary")
 
 io.stdin:read("*line")