diff --git a/main.nf b/main.nf
index 6eeea69..4d55601 100644
--- a/main.nf
+++ b/main.nf
@@ -57,6 +57,7 @@ workflow get_data {
 
 workflow {
 
+    log.warn('During the first execution, nf-mouse may take some time to download the necessary modules.')
     log.info("Uses GPU: $params.use_gpu")
     // Define channel for multiqc files
     ch_multiqc_files = Channel.empty()
diff --git a/modules/local/mouse/preqc/main.nf b/modules/local/mouse/preqc/main.nf
index 435605d..2170f4e 100644
--- a/modules/local/mouse/preqc/main.nf
+++ b/modules/local/mouse/preqc/main.nf
@@ -20,12 +20,16 @@ process PRE_QC {
     script:
     def prefix = task.ext.prefix ?: "${meta.id}"
     def b0_threshold = task.ext.b0_thr_extract_b0 ? "--b0_threshold $task.ext.b0_thr_extract_b0" : ""
+    def threshold = task.ext.b0_thr_extract_b0 ? "$task.ext.b0_thr_extract_b0" : ""
 
     """
     echo "This module is highly experimental"
     echo "Be careful with the output."
     echo ""
 
+    # Fetch b-values.
+    awk -v thr=${threshold} '{for(i=1;i<=NF;i++) if(\$i < thr) \$i=0.0; else \$i=int(\$i*10+(\$i>=0?0.5:-0.5))/10; print}' $bval > ${prefix}__stride_dwi.bval
+
     # Fetch strides.
     strides=\$(mrinfo $dwi -strides)
     # Compare strides
@@ -36,7 +40,6 @@ process PRE_QC {
 
         mrconvert $dwi ${prefix}__stride_dwi.nii.gz -strides 1,2,3,4
         scil_gradients_modify_axes.py $bvec ${prefix}__stride_dwi.bvec -1 2 3
-        cp $bval ${prefix}__stride_dwi.bval
     
     elif [ "\$strides" == "1 -2 3 4" ]; then
         echo "Strides are not (1,2,3,4), converting to 1,2,3,4."
@@ -45,17 +48,14 @@ process PRE_QC {
 
         mrconvert $dwi ${prefix}__stride_dwi.nii.gz -strides 1,2,3,4
         cp $bvec ${prefix}__stride_dwi.bvec
-        cp $bval ${prefix}__stride_dwi.bval
 
     elif [ "\$strides" == "1 2 3 4" ]; then
         echo "Strides are already 1,2,3,4"
         cp $dwi ${prefix}__stride_dwi.nii.gz
-        cp $bval ${prefix}__stride_dwi.bval
         cp $bvec ${prefix}__stride_dwi.bvec
     else
         echo "Strides are: \$strides"
         echo "There is no automatic way to transform to 1,2,3,4."
-        cp $bval ${prefix}__stride_dwi.bval
         cp $bvec ${prefix}__stride_dwi.bvec
     fi