commit 3bc02ca6fc075c82e38fcab2489125a91b2527b1
Author: Ian Skinner <56081713+IanSkinner1982@users.noreply.github.com>
Date:   Sat Aug 19 20:56:37 2023 -0400

diff --git a/extract-gigaleak-csu.sh b/extract-gigaleak-csu.sh
new file mode 100644
index 0000000..97dd61b
--- /dev/null
+++ b/extract-gigaleak-csu.sh
@@ -0,0 +1,66 @@
+#   extract-gigaleak-csu
+#   Lillian Skinner
+#   Last modified 2023/08/19
+# Extracts firmware CIAs from the RomFS of "SystemUpdater-0_13-0927-UnFixedKey.csu". This can't be done with other tools as 0.13.0 doesn't use the normal RomFS format.
+# So far this only gets the start/end addresses of the CIAs.
+
+echo "Finding CIA headers in file..."
+od -t x -A d romfs.bin | grep "00002020 00000000 00000a00 00000350" | sed 's/ .*//' | sed 's/^0*//' > romfs-dir.txt
+# Get start address of every CIA header and store to file
+echo "Found all headers!"
+echo "================================================="
+
+declare -i x=0
+declare -i i=1
+
+echo "Extracting odd CIAs..."
+echo "================================================="
+sed 1d romfs-dir.txt | while IFS=, read -r START_HEADER; read NEXT_HEADER
+do
+    echo "CIA $i header at         ${START_HEADER}"
+    echo "Next header at           ${NEXT_HEADER}"
+    echo "Finding CIA $i end from CIA $((i + 1)) header... "
+    y="00"
+    x=0
+    z="00"
+    while [ "$y" = "00" ]; do
+        x+=1
+        y=$(od -j $((NEXT_HEADER - x)) -N 1 -x -A n romfs.bin | sed 's|[ ,]||g' | sed 's/^..//');
+        # Get bytes one backwards from next header
+        # printf '%x\n' $((NEXT_HEADER - x))
+        # echo $y
+        # echo $x
+    done
+    echo "End found!"
+    echo "Non-zerobyte ($y) at $((NEXT_HEADER - x))"
+    echo "Padding from CIA $i to $((i + 1)) is $((x - 1)) bytes."
+    echo "CIA $i done!"
+    echo "================================================="
+    i+=2
+done < romfs-dir.txt
+
+echo "Extracting even CIAs..."
+echo "================================================="
+sed 1d romfs-dir.txt | while IFS=, read -r START_HEADER; read NEXT_HEADER
+do
+    echo "CIA $i header at         ${START_HEADER}"
+    echo "Next header at           ${NEXT_HEADER}"
+    echo "Finding CIA $i end from CIA $((i + 1)) header... "
+    y="00"
+    x=0
+    z="00"
+    while [ "$y" = "00" ]; do
+        x+=1
+        y=$(od -j $((NEXT_HEADER - x)) -N 1 -x -A n romfs.bin | sed 's|[ ,]||g' | sed 's/^..//');
+        # Get bytes one backwards from next header
+        # printf '%x\n' $((NEXT_HEADER - x))
+        # echo $y
+        # echo $x
+    done
+    echo "End found!"
+    echo "Non-zerobyte ($y) at $((NEXT_HEADER - x))"
+    echo "Padding from CIA $i to $((i + 1)) is $((x - 1)) bytes."
+    echo "CIA $i done!"
+    echo "================================================="
+    i+=2
+done
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