flake: check firmware for potentially overlapping code

flake.nix

@@ -175,6 +175,40 @@
             }" ${fwtype}
           '';
 
+          checkPhase = ''
+            # check if the overlapping RTIO/DMA/batch sections
+            # don't overwrite other parts
+            max_size=2048  # half the page size (see link.x)
+
+            sections_to_check=(
+                ".rtio_page"
+                ".rtio_wide_page"
+                ".dma_page"
+                ".dma_wide_page"
+                ".batch_page"
+                ".batch_wide_page"
+            )
+
+            objdump_output=$(objdump -h "../build/firmware/armv7-none-eabihf/release/${fwtype}")
+
+            for section in "''${sections_to_check[@]}"; do
+                line=$(echo "$objdump_output" | grep -w "$section" || true)
+                
+                if [ -z "$line" ]; then
+                    echo "ERROR: section $section not found"
+                    exit 1
+                fi
+
+                size_hex=$(echo "$line" | awk '{print $3}')
+                size_dec=$((16#$size_hex))
+
+                if [ "$size_dec" -ge "$max_size" ]; then
+                    echo "ERROR: section $section ($size_dec bytes) exceeds $max_size bytes."
+                    exit 1
+                fi
+            done
+          '';
+
           installPhase = ''
             mkdir -p $out $out/nix-support
             cp ../build/${fwtype}.bin $out/${fwtype}.bin
@@ -183,7 +217,7 @@
             echo file binary-dist $out/${fwtype}.elf >> $out/nix-support/hydra-build-products
           '';
 
-          doCheck = false;
+          doCheck = true;
           dontFixup = true;
         };
       };