diff --git a/pybar/daq/fifo_readout.py b/pybar/daq/fifo_readout.py
index <HASH>..<HASH> 100644
--- a/pybar/daq/fifo_readout.py
+++ b/pybar/daq/fifo_readout.py
@@ -100,9 +100,8 @@ class FifoReadout(object):
         else:

             fifo_size = self.dut['SRAM']['FIFO_SIZE']

             data = self.read_data()

-            event_selector = logical_or(is_data_record, is_data_header)

-            events = data[event_selector(data)]

-            if events.shape[0] != 0:

+            dh_sr_select = logical_and(is_fe_word, logical_or(is_data_record, is_data_header))

+            if np.count_nonzero(dh_sr_select) != 0:

                 logging.warning('SRAM FIFO containing events when starting FIFO readout: FIFO_SIZE = %i', fifo_size)

         self._words_per_read.clear()

         if clear_buffer:
ENH: optimize check, reduce memory, check for FE data word