diff --git a/build/docker/Dockerfile.demo-pinecone b/build/docker/Dockerfile.demo-pinecone
index a23233a7..dee77a67 100644
--- a/build/docker/Dockerfile.demo-pinecone
+++ b/build/docker/Dockerfile.demo-pinecone
@@ -1,6 +1,6 @@
 #syntax=docker/dockerfile:1.2
 
-FROM --platform=${BUILDPLATFORM} ghcr.io/element-hq/dendrite-monolith:binaries AS build
+FROM --platform=${TARGETPLATFORM} ghcr.io/element-hq/dendrite-monolith:binaries AS build
 
 FROM alpine:latest
 RUN apk --update --no-cache add curl
diff --git a/build/docker/Dockerfile.demo-yggdrasil b/build/docker/Dockerfile.demo-yggdrasil
index 32a7db4d..8522e030 100644
--- a/build/docker/Dockerfile.demo-yggdrasil
+++ b/build/docker/Dockerfile.demo-yggdrasil
@@ -1,6 +1,6 @@
 #syntax=docker/dockerfile:1.2
 
-FROM --platform=${BUILDPLATFORM} ghcr.io/element-hq/dendrite-monolith:binaries AS build
+FROM --platform=${TARGETPLATFORM} ghcr.io/element-hq/dendrite-monolith:binaries AS build
 
 FROM alpine:latest
 LABEL org.opencontainers.image.title="Dendrite (Yggdrasil demo)"