diff --git a/docs/source/whats_new.rst b/docs/source/whats_new.rst
index 40a3161b6..2ae601cc8 100644
--- a/docs/source/whats_new.rst
+++ b/docs/source/whats_new.rst
@@ -21,6 +21,8 @@ Enhancements
 Bugs
 ~~~~
 
+- Fix Stieger2021 dataset bugs (:gh:`651` by `Martin Wimpff`_)
+
 API changes
 ~~~~~~~~~~~
 
diff --git a/moabb/datasets/stieger2021.py b/moabb/datasets/stieger2021.py
index ae9305857..808e4ccb3 100644
--- a/moabb/datasets/stieger2021.py
+++ b/moabb/datasets/stieger2021.py
@@ -227,8 +227,9 @@ def _get_single_subject_data(self, subject):
                     and (container.TrialData[i].triallength + 2) > self.interval[1]
                 ):
                     # this should be the cue time-point
-                    if container.time[i][2 * srate] == 0:
-                        raise ValueError("This should be the cue time-point,")
+                    assert (
+                        container.time[i][2 * srate] == 0
+                    ), "This should be the cue time-point"
                     stim[2 * srate] = y
                 X_flat.append(x)
                 stim_flat.append(stim[None, :])
@@ -263,7 +264,11 @@ def _get_single_subject_data(self, subject):
                 badchanidxs = []
 
             for idx in badchanidxs:
-                used_channels = ch_names if self.channels is None else self.channels
+                used_channels = (
+                    ch_names
+                    if (not hasattr(self, "channels") or self.channels is None)
+                    else self.channels
+                )
                 if eeg_ch_names[idx - 1] in used_channels:
                     raw.info["bads"].append(eeg_ch_names[idx - 1])
 
@@ -276,5 +281,5 @@ def _get_single_subject_data(self, subject):
                     bad_info=raw.info["bads"],
                 )
 
-            subject_data[session] = {"run_0": raw}
+            subject_data[str(session)] = {"0": raw}
         return subject_data