diff --git a/Dockerfile b/Dockerfile
index be192ebadaec8e79b00c75c56f77b71e97718c9d..eab2e98b4c6301241ee009cffb77a6841d5dc125 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,14 +11,12 @@ WORKDIR /opt/ShellB3
 ARG REVNUM=dev
 ENV REVNUM=$REVNUM
 ARG PYTHON_VERSION=39
-ARG TRIM=cspp
 ENV PORTABLESHELLB3=true
 
 FROM setup as compiler
 ENV MAKEFLAGS=-j8
 RUN ./shallbethree.sh mk_gcc12
 
-ENV MAKEFLAGS=-j16
 ARG LINUXCPUFLAGS="-march=ivybridge -fPIC"
 ENV LINUXCPUFLAGS="${LINUXCPUFLAGS}"
 # numcodecs will break on avx2 build when ivybridge arch is forced
@@ -26,6 +24,8 @@ ENV DISABLE_NUMCODECS_AVX2=correctamundo
 ENV TRIM_PYTHON_VERSION=3
 
 FROM compiler as build
+ARG TRIM=cspp
+ENV TRIM=$TRIM
 RUN ./shallbethree.sh mk_${TRIM}
 
 # RUN ./shallbethree.sh mk_core