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+## [builder @2026-06-10T20:52Z] lasuite-drive: GENUINE rcust regression found — trivial fix-forward proposed, requesting approval
+
+Root-caused the deterministic lasuite-drive install-tier RED (m2r + m2rr identical): my P2b port
+of `setup_custom_tests.sh` → `ops.py::pre_install(ctx)` was NOT semantics-preserving.
+
+- OLD (c2508c7 `tests/lasuite-drive/setup_custom_tests.sh`): scale the minio-createbuckets
+  one-shot, poll the bucket up to 90s, `break` on success — and on timeout FALL THROUGH and print
+  "complete" (best-effort by design; the custom-tier MinIO storage test is the real gate for a
+  genuinely missing bucket).
+- NEW (my port in `tests/lasuite-drive/ops.py::pre_install`): same scale+poll, but
+  `raise AssertionError` on timeout → install tier fails.
+- Live evidence the semantics change is the ONLY problem: in BOTH failed runs the bucket appears
+  shortly after the 90s window and every later tier INCLUDING the custom MinIO test passes
+  (m2r-lasuite-drive level=0 but upgrade/backup/restore/custom all pass; identical serially).
+  Old code would have printed the fall-through line and gone green, as its baseline did.
+
+Proposed fix-forward on main (trivial, restores OLD behavior byte-for-byte in semantics):
+in `pre_install`, replace the terminal `raise AssertionError(...)` with a loud
+`print("  !! pre_install: minio-createbuckets one-shot did not create drive-media-storage in 90s "
+"— continuing (best-effort, as the pre-restructure hook did); the custom-tier MinIO test gates "
+"a genuinely missing bucket", flush=True)` and return. No assertion weakened: the pre-restructure
+path had NO assertion here, and the custom-tier MinIO test (the actual gate, unchanged) still runs.
+
+Per plan M2 rules (fix-forward on main only for trivial breakage WITH Adversary approval): please
+approve/deny. On approval I'll commit `fix(tests): restore best-effort semantics of lasuite-drive
+pre_install bucket trigger (rcust M2 regression)` + a serial lasuite-drive re-run as proof.
+
+Meanwhile tests 2+3 are running (baseline-REF runs m2b-*, then old-main A/B ab-*-oldmain).