diff --git a/fb/aarch64/.gitkeep b/fb/aarch64/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/fb/fabric-test-cart-plot.png b/fb/amd64/fabric-test-cart-plot.png
similarity index 100%
rename from fb/fabric-test-cart-plot.png
rename to fb/amd64/fabric-test-cart-plot.png
diff --git a/fb/qemu-screenshot-20260807-105238.png b/fb/amd64/qemu-screenshot-20260807-105238.png
similarity index 100%
rename from fb/qemu-screenshot-20260807-105238.png
rename to fb/amd64/qemu-screenshot-20260807-105238.png
diff --git a/fb/qemu-screenshot-20260807-113612.png b/fb/amd64/qemu-screenshot-20260807-113612.png
similarity index 100%
rename from fb/qemu-screenshot-20260807-113612.png
rename to fb/amd64/qemu-screenshot-20260807-113612.png
diff --git a/fb/riscv64/.gitkeep b/fb/riscv64/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/scripts/qemu_screenshot.sh b/scripts/qemu_screenshot.sh
index 38531b8..67fb460 100755
--- a/scripts/qemu_screenshot.sh
+++ b/scripts/qemu_screenshot.sh
@@ -11,7 +11,8 @@
 # Outputs:
 #   <BUILD_DIR>/screenshot.ppm                 — raw PPM from QEMU screendump
 #   <LOG_DIR>/qemu-screenshot-YYYYMMDD-HHMMSS.log  — serial log
-#   fb/qemu-screenshot-YYYYMMDD-HHMMSS.png         — PNG (tracked in git, not build/)
+#   fb/amd64/qemu-screenshot-YYYYMMDD-HHMMSS.png   — PNG (tracked in git, not build/)
+#   (amd64-only script; fb/ has one subdirectory per ISA by convention)
 #
 # Requires: qemu-system-x86_64, socat, xorriso, mtools, ovmf, imagemagick
 
@@ -62,7 +63,7 @@ fi
 # --------------------------------------------------------------------------
 # Setup paths
 # --------------------------------------------------------------------------
-FB_DIR="fb"
+FB_DIR="fb/amd64"
 mkdir -p "${LOG_DIR}" "${BUILD_DIR}" "${FB_DIR}"
 
 TS=$(date +%Y%m%d-%H%M%S)