diff --git a/tests/gnrc_tcp/tests/05-garbage-pkts.py b/tests/gnrc_tcp/tests/05-garbage-pkts.py
index ce92a22c637be..955758ee212ac 100755
--- a/tests/gnrc_tcp/tests/05-garbage-pkts.py
+++ b/tests/gnrc_tcp/tests/05-garbage-pkts.py
@@ -7,6 +7,7 @@
 # directory for more details.
 
 import base64
+import pexpect
 import os
 import socket
 import sys
@@ -96,6 +97,17 @@ def test_short_header(child, src_if, src_ll, dst_if, dst_l2, dst_ll, dst_port):
 @testfunc
 def test_send_ack_instead_of_syn(child, src_if, src_ll,
                                  dst_if, dst_l2, dst_ll, dst_port):
+    # check if entering _event_loop in `@testfunc` decorator generates debug
+    # output
+    debug = child.expect([pexpect.TIMEOUT, 'GNRC_TCP'], timeout=1)
+    # with debug output the node can be overwhelmed by packets + output
+    if debug:
+        count = 10
+    else:
+        count = 1000
+
+    print(debug)
+    print(count)
     # see https://github.com/RIOT-OS/RIOT/pull/12001
     provided_data = base64.b64decode("rwsQf2pekYLaU+exUBBwgPDKAAA=")
     tcp_hdr = TCP(provided_data)
@@ -103,7 +115,7 @@ def test_send_ack_instead_of_syn(child, src_if, src_ll,
     # set destination port to application specific port
     tcp_hdr.dport = dst_port
     sendp(Ether(dst=dst_l2) / IPv6(src=src_ll, dst=dst_ll) / tcp_hdr,
-          iface=src_if, verbose=0, count=1000)
+          iface=src_if, verbose=0, count=count)
 
     # check if server actually still works
     with socket.socket(socket.AF_INET6, socket.SOCK_STREAM) as sock:
@@ -140,7 +152,7 @@ def test_option_parsing_term(child, src_if, src_ll,
              if type(getattr(script, t)).__name__ == "function"
              and t.startswith("test_")]
     for test in tests:
-        res = run(test, timeout=10, echo=False)
+        res = run(test, timeout=10, echo=True)
         if res != 0:
             sys.exit(res)
     print(os.path.basename(sys.argv[0]) + ": success\n")