diff --git a/CHANGELOG b/CHANGELOG
index 6eac388..deb8979 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,4 @@
+2022-07-15: bugfix for upload_*_firmware_from_hex.py [5309e5f]
 2022-04-02: new firmware: HW calibration signal output via T2OUT pin (HW change) [ecd6302]
 2022-03-21: Fix #15 - install Linux files only when building under Linux [be76527]
 2022-03-14: More refactoring [5d434c2]
diff --git a/examples/capture_6022.py b/examples/capture_6022.py
index 601d37f..4b8a0f2 100755
--- a/examples/capture_6022.py
+++ b/examples/capture_6022.py
@@ -135,6 +135,8 @@
 # scale the data packets and write them into the outfile
 #
 def pcb( ch1_data, ch2_data ):
+    # use these global vaiables
+    global skip1st,totalsize,dc1,dc2,rms1,rms2,timestep,start_time
     # define "static" variables
     if 'av1' not in pcb.__dict__:
         pcb.av1 = 0