diff --git a/ci/Jenkinsfile.prs b/ci/Jenkinsfile.prs
index 41fa2dd13..9e69d6d30 100644
--- a/ci/Jenkinsfile.prs
+++ b/ci/Jenkinsfile.prs
@@ -7,7 +7,12 @@ pipeline {
     string(
       name: 'NIMFLAGS',
       description: 'Flags for Nim compilation.',
-      defaultValue: params.NIMFLAGS ?: '-d:disableMarchNative -d:insecure --parallelBuild:6'
+      defaultValue: params.NIMFLAGS ?: [
+        '--colors:off',
+        '-d:insecure',
+        '-d:disableMarchNative',
+        '--parallelBuild:6',
+      ].join(' ')
     )
     string(
       name: 'LOG_LEVEL',
diff --git a/ci/Jenkinsfile.release b/ci/Jenkinsfile.release
index d2dd256b1..6da215a23 100644
--- a/ci/Jenkinsfile.release
+++ b/ci/Jenkinsfile.release
@@ -33,7 +33,12 @@ pipeline {
     string(
       name: 'NIMFLAGS',
       description: 'Flags for Nim compilation.',
-      defaultValue: params.NIMFLAGS ?: '-d:disableMarchNative -d:chronicles_colors:none -d:insecure',
+      defaultValue: params.NIMFLAGS ?: [
+        '--colors:off',
+        '-d:disableMarchNative',
+        '-d:chronicles_colors:none',
+        '-d:insecure',
+      ].join(' ')
     )
   }