diff --git a/cosmo-yices/Dockerfile b/cosmo-yices/Dockerfile
index 450454b..98512fc 100644
--- a/cosmo-yices/Dockerfile
+++ b/cosmo-yices/Dockerfile
@@ -1,17 +1,17 @@
 # MAIN: https://yices.csl.sri.com/
 # REPO: https://github.com/SRI-CSL/yices2/
 FROM localhost/notwa-util AS downloader
-ENV YICES_COMMIT=d28304671590ed04f13ce930aaae27015542c8ea
-ENV YICES_SHA256=f1bd9979a9070e515fdc60d07836912e0058263f431b9b1a18f8975be1b95242
+ARG YICES_COMMIT=d28304671590ed04f13ce930aaae27015542c8ea
+ARG YICES_SHA256=f1bd9979a9070e515fdc60d07836912e0058263f431b9b1a18f8975be1b95242
 # MAIN: https://gmplib.org/
 # REPO: https://gmplib.org/repo/
-ENV GMP_VERSION=6.2.1
-ENV GMP_SHA256=fd4829912cddd12f84181c3451cc752be224643e87fac497b69edddadc49b4f2
+ARG GMP_VERSION=6.2.1
+ARG GMP_SHA256=fd4829912cddd12f84181c3451cc752be224643e87fac497b69edddadc49b4f2
 # MAIN: http://fmv.jku.at/kissat/
 # REPO: https://github.com/arminbiere/kissat
 # FORK: https://github.com/BrunoDutertre/kissat
-ENV KISSAT_COMMIT=315cd3227fd2321d29d10f7d8572011bf00174a5
-ENV KISSAT_SHA256=031fca7efcb17c6f1921dd056052bd373de724e445fc2ed37bfdd5954148119f
+ARG KISSAT_COMMIT=315cd3227fd2321d29d10f7d8572011bf00174a5
+ARG KISSAT_SHA256=031fca7efcb17c6f1921dd056052bd373de724e445fc2ed37bfdd5954148119f
 
 RUN --mount=type=cache,id=common,target=/media/common,sharing=locked \
     --mount=type=tmpfs,target=/tmp : \
diff --git a/notwa-util/Dockerfile b/notwa-util/Dockerfile
index 05c7621..0dc599a 100644
--- a/notwa-util/Dockerfile
+++ b/notwa-util/Dockerfile
@@ -10,8 +10,8 @@ WORKDIR /media/common
 
 FROM partial as downloader
 # this demonstrates how to use the `acquire` script.
-ENV BUSYBOX_VERSION=1.35.0
-ENV BUSYBOX_SHA256=faeeb244c35a348a334f4a59e44626ee870fb07b6884d68c10ae8bc19f83a694
+ARG BUSYBOX_VERSION=1.35.0
+ARG BUSYBOX_SHA256=faeeb244c35a348a334f4a59e44626ee870fb07b6884d68c10ae8bc19f83a694
 RUN --mount=type=cache,id=common,target=/media/common,sharing=locked \
     --mount=type=tmpfs,target=/tmp : \
  && name=busybox \