diff --git a/.github/workflows/build-iso.yml b/.github/workflows/build-iso.yml
index a75630a..06b0b46 100644
--- a/.github/workflows/build-iso.yml
+++ b/.github/workflows/build-iso.yml
@@ -43,7 +43,7 @@ jobs:
             --privileged
             -v ${{ github.workspace }}:/work
             -v /dev:/dev
-            --tmpfs /tmp:rw,nosuid,nodev,exec,size=8G
+            --tmpfs /tmp:rw,nosuid,nodev,exec,size=16G
           run: |
             set -euxo pipefail
 
@@ -79,6 +79,9 @@ jobs:
             # livecd-creator (livecd-tools) — purpose-built for live ISOs.
             # Handles EFI/BOOT + isohybrid + grafting that livemedia-creator
             # --make-iso --no-virt does not. Produces UEFI+BIOS bootable ISO.
+            # --tmpdir /var/lmc to avoid GitHub Actions /tmp tmpfs constraints.
+            # /var on the runner is the host's ext4 (~80GB free post-disk-cleanup).
+            mkdir -p /var/lmc /var/lmc-cache
             livecd-creator \
               --verbose \
               --config kickstart/veilor-os-ci.ks \
@@ -86,8 +89,8 @@ jobs:
               --title "veilor-os" \
               --product "veilor-os" \
               --releasever "${{ github.event.inputs.releasever || '43' }}" \
-              --tmpdir /tmp \
-              --cache /tmp/veilor-cache 2>&1 | tee build/out/build.log
+              --tmpdir /var/lmc \
+              --cache /var/lmc-cache 2>&1 | tee build/out/build.log
 
             # Move output ISO to expected dir
             mv ./veilor-os-43.iso build/out/ 2>/dev/null || mv ./*.iso build/out/ 2>/dev/null || true