diff --git a/tasks/enduro-trails/reports/tri/tri-chuvash-z10.png b/tasks/enduro-trails/reports/tri/tri-chuvash-z10.png
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diff --git a/tasks/enduro-trails/reports/tri/tri-hillshade-chuvash-z12.png b/tasks/enduro-trails/reports/tri/tri-hillshade-chuvash-z12.png
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diff --git a/tasks/enduro-trails/reports/tri/tri-moscow-z10.png b/tasks/enduro-trails/reports/tri/tri-moscow-z10.png
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diff --git a/tasks/enduro-trails/scripts/patch_tri_ui.sh b/tasks/enduro-trails/scripts/patch_tri_ui.sh
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--- /dev/null
+++ b/tasks/enduro-trails/scripts/patch_tri_ui.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+set -e
+
+FILE="/home/slin/enduro-trails/prototype/static/app.js"
+
+# 1. In onTerrainCheckbox(): add triChecked + localStorage + applyTerrainLayer
+# After line with hillshadeChecked declaration (line 2672), add triChecked
+sed -i '2672a\  const triChecked = document.getElementById('\''terrain-tri-cb'\'').checked;' "$FILE"
+
+# After localStorage hillshade (now line 2677 because we added 1 line), add tri localStorage
+sed -i '2677a\  localStorage.setItem('\''terrain-tri'\'', triChecked ? '\''1'\'' : '\''0'\'');' "$FILE"
+
+# Update active state to include tri (line with btn.classList.toggle)
+# Now at line 2681 (shifted by 2)
+sed -i 's/btn.classList.toggle('\''active'\'', hypsoChecked || hillshadeChecked)/btn.classList.toggle('\''active'\'', hypsoChecked || hillshadeChecked || triChecked)/' "$FILE"
+
+# After applyTerrainLayer hillshade line, add TRI layer
+# Find the hillshade applyTerrainLayer line and add after it
+sed -i '/applyTerrainLayer.*terrain-hillshade.*hillshadeChecked/a\  applyTerrainLayer('\''terrain-tri'\'', TERRAIN_BASE_URL + '\''/tri/{z}/{x}/{y}.png'\'', triChecked, 0.70, 5, 15);' "$FILE"
+
+# 2. In restoreTerrainState(): add tri restore
+# After "const hillshade = localStorage..." line
+sed -i '/const hillshade = localStorage.getItem.*terrain-hillshade/a\  const tri = localStorage.getItem('\''terrain-tri'\'') === '\''1'\'';' "$FILE"
+
+# After "const hillshadeCb = document.getElementById..."
+sed -i '/const hillshadeCb = document.getElementById/a\  const triCb = document.getElementById('\''terrain-tri-cb'\'');' "$FILE"
+
+# After "if (hillshadeCb) hillshadeCb.checked = hillshade;"
+sed -i '/if (hillshadeCb) hillshadeCb.checked = hillshade;/a\  if (triCb) triCb.checked = tri;' "$FILE"
+
+# Update the "if (hypso || hillshade)" to include tri
+sed -i 's/if (hypso || hillshade) {/if (hypso || hillshade || tri) {/' "$FILE"
+
+# Update btn active state in restoreTerrainState
+sed -i "s/if (btn) btn.classList.toggle('active', hypso || hillshade);/if (btn) btn.classList.toggle('active', hypso || hillshade || tri);/" "$FILE"
+
+echo "Patching done. Verifying..."
+grep -n "terrain-tri" "$FILE"
+echo "---"
+grep -n "triChecked\|triCb\| tri " "$FILE" | head -15