diff --git a/docker/Dockerfile.base b/docker/Dockerfile.base
index b20da2a7..58d250ab 100644
--- a/docker/Dockerfile.base
+++ b/docker/Dockerfile.base
@@ -14,7 +14,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libvulkan-dev \
   pybind11-dev
 WORKDIR /root
-RUN git clone https://github.com/iqtlabs/gr-iqtlabs -b 1.0.113
+RUN git clone https://github.com/iqtlabs/gr-iqtlabs -b 1.0.114
 COPY --from=iqtlabs/gamutrf-vkfft:latest /root /root/gr-iqtlabs
 WORKDIR /root/gr-iqtlabs/build
 COPY --from=iqtlabs/gamutrf-sigmf:latest /usr/local /usr/local
diff --git a/gamutrf/grscan.py b/gamutrf/grscan.py
index 5bd4555d..9b5d01b7 100644
--- a/gamutrf/grscan.py
+++ b/gamutrf/grscan.py
@@ -390,9 +390,8 @@ def __init__(
                     (block, "inference"), (self.inference_output_block, "inference")
                 )
 
-        if not retune_fft_output_block:
-            retune_fft_output_block = blocks.null_sink(gr.sizeof_float * nfft)
-        self.connect((retune_fft, 0), (retune_fft_output_block, 0))
+        if retune_fft_output_block:
+            self.connect((retune_fft, 0), (retune_fft_output_block, 0))
 
         if pretune:
             self.msg_connect((self.retune_pre_fft, "tune"), (self.sources[0], cmd_port))