diff --git a/yardline-rc/BUILD.md b/yardline-rc/BUILD.md
index 16ae5ca8..49ecee47 100644
--- a/yardline-rc/BUILD.md
+++ b/yardline-rc/BUILD.md
@@ -33,6 +33,25 @@ with `import.meta.env.BASE_URL` (or a relative base) so a rebuild stays correct.
After ANY rebuild, verify no `` `/assets/ `` remain:
`grep -c '`/assets/' assets/index-*.js` must be 0.
+**Phone-controller bridge (patched 2026-07-24):** the source builds embed a
+bridge that (a) tells the console shell which phone pad to show per race phase
+via `postMessage({type:"sc:controls", …})` and (b) receives the phone's
+`sc:analog` driving frames + `sc:intent` button presses back. The 2026-07-23
+deduped rebuild came from a source tree WITHOUT that bridge, so the phone fell
+back to a d-pad and no input reached the car — the cars rendered but were
+undrivable from a phone. Restored here without a rebuild:
+- `index.html` carries an inline `