diff --git a/scripts/test_.py b/scripts/test_.py
index 1a13c5b..4593b40 100755
--- a/scripts/test_.py
+++ b/scripts/test_.py
@@ -304,8 +304,8 @@ class ReentrantTestCase(TestCase):
 
             # exact cycle we should drop into debugger?
             if gdb and failure and failure.cycleno == cycles:
-                return super().test(gdb=gdb,
-                    persist=persist, failure=failure, **args)
+                return super().test(gdb=gdb, persist=persist, cycles=cycles,
+                    failure=failure, **args)
 
             # run tests, but kill the program after prog/erase has
             # been hit n cycles. We exit with a special return code if the
@@ -327,7 +327,7 @@ class TestSuite:
             self.name = self.name[:-len('.toml')]
         self.path = path
         self.classes = classes
-        self.defines = defines
+        self.defines = defines.copy()
         self.filter = filter
 
         with open(path) as f:
diff --git a/testbd/lfs_testbd.c b/testbd/lfs_testbd.c
index f13140e..0fae6bf 100644
--- a/testbd/lfs_testbd.c
+++ b/testbd/lfs_testbd.c
@@ -199,7 +199,7 @@ int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
         bd->power_cycles -= 1;
         if (bd->power_cycles == 0) {
             // sync to make sure we persist the last changes
-            lfs_testbd_rawsync(cfg);
+            assert(lfs_testbd_rawsync(cfg) == 0);
             // simulate power loss
             exit(33);
         }
@@ -241,7 +241,7 @@ int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
         bd->power_cycles -= 1;
         if (bd->power_cycles == 0) {
             // sync to make sure we persist the last changes
-            lfs_testbd_rawsync(cfg);
+            assert(lfs_testbd_rawsync(cfg) == 0);
             // simulate power loss
             exit(33);
         }
diff --git a/tests_/test_files.toml b/tests_/test_files.toml
index da132f2..565e665 100644
--- a/tests_/test_files.toml
+++ b/tests_/test_files.toml
@@ -60,7 +60,7 @@ code = '''
 [[case]] # rewriting files
 define.SIZE1 = [32, 8192, 131072, 0, 7, 8193]
 define.SIZE2 = [32, 8192, 131072, 0, 7, 8193]
-define.CHUNKSIZE = [31, 16, 1, 1025]
+define.CHUNKSIZE = [31, 16, 1]
 code = '''
     lfs_format(&lfs, &cfg) => 0;
 
@@ -142,7 +142,7 @@ code = '''
 [[case]] # appending files
 define.SIZE1 = [32, 8192, 131072, 0, 7, 8193]
 define.SIZE2 = [32, 8192, 131072, 0, 7, 8193]
-define.CHUNKSIZE = [31, 16, 1, 1025]
+define.CHUNKSIZE = [31, 16, 1]
 code = '''
     lfs_format(&lfs, &cfg) => 0;
 
@@ -219,7 +219,7 @@ code = '''
 [[case]] # truncating files
 define.SIZE1 = [32, 8192, 131072, 0, 7, 8193]
 define.SIZE2 = [32, 8192, 131072, 0, 7, 8193]
-define.CHUNKSIZE = [31, 16, 1, 1025]
+define.CHUNKSIZE = [31, 16, 1]
 code = '''
     lfs_format(&lfs, &cfg) => 0;