diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index f442bc7..69634bd 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -161,7 +161,8 @@ Blanton_TTL_Script/
     └── Script_ABC_Blanton/            # ← Tera Term 的工作目錄（整包給測試員）
         │
         ├── 4_Blanton_Script_thermal_safety.ttl  # 熱 / 安規：獨立跑，不接 A→B→C
-        ├── 5_Blanton_Script_Reboot_Cycle.ttl    # 重開機循環：獨立跑，while 1 無止境（未上機驗證）
+        ├── 5_Blanton_Script_Boot_Cycle.ttl      # 開機循環（warm / cold，EN_Cold_Warm_boot）：獨立跑，while 1 無止境
+        ├── 6_Blanton_Script_BER_Cycle.ttl       # Diag ↔ SONiC 冷開機循環，兩邊各量一次 unit 0 BER：獨立跑，while 1
         ├── config.ttl                 # 全域設定：testcase 名、EN_Margin / EN_TX_FIR / EN_log / EN_timestamp、
         │                              #   風扇與 SWB 宣告、SSD/USB/BMC_USB 壓力秒數、三個 prompt 字串
         ├── hammer/                    # 🚫 gitignored — mlucas ELF binary（~99 MB），DUT image 自帶，
@@ -219,6 +220,7 @@ Blanton_TTL_Script/
             ├── ddr5_temp.sh               # DDR5 DIMM 溫度（SPD5118 @ i2c-5 0x50/0x51，reg 0x31）
             ├── hsc_temp_readback.sh       # LTC4287 HSC 溫度（i2c-28 0x40/0x45，內/外部感溫）
             ├── avt_pmpower.sh             # AMD CPU 封裝功耗（AVTCMD pmm get_pmdata；AVT 是 NDA，不隨包）
+            ├── tray_id_stress.sh          # Tray ID I2C stress（bus 34/35/38/39 0x70 reg 0x02，寫 0xA5/0x5A 讀回）
             ├── usb_target.sh              # 偵測 USB 裝置節點／掛載點（排除系統碟）
             ├── bmc_monitor.sh             # BMC 監控：free -m + I2C 寫入/讀回圖樣測試
             ├── bmc_monitor_ddr.sh         # ⚠️ 已停用：V1.1.9 起 B/C 內的註解區塊已刪除，DDR 壓力走 bgctl + bmc-manager
@@ -381,7 +383,7 @@ PROFILE_CHANNELS=( "0:high:8" "1:low:8" ... )   # "channel:operation:change_perc
 
 | 模組 | 進入點 | 功能 |
 |------|--------|------|
-| **Script A（Pre-test）** | `1_Blanton_Script_A.ttl` V1.2.3 | root 登入 → `date -s` 對時 → 清 job log → **收掉前一輪殘留**（`hw-test-session finish` → `bgctl reset --yes` → `bgctl stop --all` → `bgctl list` 確認清空）→ `hw-test-session start` → **設定風扇轉速** → **等資料面就緒**（`wait_init.ttl`）→ DUT 清單（boot/version/fwutil/syseeprom/ssdhealth/TPM/NVMe）→ BMC enroll + version/status → source bash 工具 → 清/讀 7 組 PCIe AER + `ras-mc-ctl --summary` → `lspci` → margin → PMON → dmesg → **10G/1G 管理網路 ping** → **NFC 基線**（start → 30s → stop → report）→ 100G uplink 設定與狀態 → **BER 基線掃描**（依 `SWB_UNIT`，V1.2.1 新增）→ **一輪流量基線** → **SerDes DSC 基線**（`EN_TX_FIR`）→ `show uptime` |
+| **Script A（Pre-test）** | `1_Blanton_Script_A.ttl` V1.2.4 | root 登入 → `date -s` 對時 → 清 job log → **收掉前一輪殘留**（`hw-test-session finish` → `bgctl reset --yes` → `bgctl stop --all` → `bgctl list` 確認清空）→ `hw-test-session start` → **設定風扇轉速** → **等資料面就緒**（`wait_init.ttl`）→ DUT 清單（boot/version/fwutil/syseeprom/ssdhealth/TPM/NVMe）→ BMC enroll + version/status → source bash 工具 → 清/讀 7 組 PCIe AER + `ras-mc-ctl --summary` → `lspci` → margin → PMON → dmesg → **10G/1G 管理網路 ping** → **NFC 基線**（start → 30s → stop → report）→ 100G uplink 設定與狀態 → **BER 基線掃描**（依 `SWB_UNIT`，V1.2.1 新增）→ **一輪流量基線** → **SerDes DSC 基線**（`EN_TX_FIR`）→ `show uptime` |
 | **Script B（Stress）** | `2_Blanton_Script_B.ttl` | **V1.1.8 起 `mlucas-avx2 -cpu 0:15` 由 `systemd-run --unit=mlucas-amm`（`Type=exec`、`Restart=always`）啟動，不再是 shell 的 `&` 背景 job** + `bgctl run` 的 `memtester` / SSD / USB 壓力（v1.1.7 起 SSD/USB 的 `--runtime`/`--passes` 讀 `config.ttl` 的 `SSD_RUNTIME`/`SSD_COUNT`、`USB_RUNTIME`/`USB_COUNT`；BMC memtester 不帶次數 = 跑到被停） + BMC DDR（`bmc-manager run memtester`）→ BMC USB net test（探測 cdc_ncm 介面，`systemd-run` 掛 `BMC_USB_RUNTIME` 秒的 ping，V1.1.8 前寫死 4 小時）→ 啟動 mgmt ping 監控 → **啟動 NFC 輪詢** → `jobs` / `systemctl is-active mlucas-amm` / `bgctl list` → traffic（依 `SWB_UNIT`）→ `while 1` 每輪 PMON + `bgctl list`/`jobs`/`systemctl is-active mlucas-amm` + `sleep 60`（**V1.1.4 起 margin 不在迴圈內**；V1.2.0 起等待走 DUT 端 `sleep` 而非 macro 端 `pause`）|
 | **Script C（Post-test）** | `3_Blanton_Script_C.ttl` | `kill $(jobs -p)` + **`systemctl stop mlucas-amm`**（systemd unit 不是 shell job，`jobs -p` 抓不到）+ `bgctl stop --all` / `reset` + 停 BMC USB unit、mgmt ping 與 **NFC 輪詢** → PMON + dmesg → 7 組 AER + `ras-mc-ctl` → BMC USB `journalctl` **寫進 `log/bmc_usb_net.log`**（不再印在 console） → `ip -s link show eth0/eth1` → `cat` mlucas log（並 `cp` 進 job 目錄一起帶走）→ **NFC `report`** → traffic `stop` + `report` → **SerDes DSC 收尾**（`EN_TX_FIR`）→ **BER 掃描**（依 `SWB_UNIT`）→ NVMe 健康 → `show reboot-cause` → **margin 掃描**（`EN_Margin`，V1.1.4 由 Script B 移來）→ `uptime` → **job log 複製到 USB（帶時戳）** → `exit` + wait『Script done』→ `hw-test-session finish` |
 | **Script 4（Thermal / Safety）** | `4_Blanton_Script_thermal_safety.ttl` | **獨立腳本，不接 A→B→C。** Script A 式的環境建立（登入 / session / 風扇 / `wait_init` / DUT 清單 / BMC / PCIe 清除 / `pcie_bus` / PMON / dmesg）→ **滿載**（`mlucas-avx2 -cpu 0:15`，V1.1.8 起與 Script B 同樣掛成 `mlucas-amm` systemd unit + `blanton_tr518.sh start`）→ `while 1`：PMON + `TH6_SWB0/1_power_readback.sh` + `avt_pmpower.sh`（CPU 封裝功耗，V1.2.3）+ `bgctl list` / `jobs` / `systemctl is-active mlucas-amm`，`pause 60`。**沒有收尾段** —— 中斷後 DUT 仍在 `port cd lb=mac` / `l2 learn off` / `test mode nr=yes`，且 CPU 仍滿載，要手動 `blanton_tr518.sh stop` + `systemctl stop mlucas-amm` |
@@ -812,7 +814,7 @@ margin status、全部 VRM 軌的 Vin/Vout/Iout/Temp、CB + ICB 溫感讀值，
 - [ ] `CHANGELOG.md`：延續三支腳本頂端的 Version History，集中成一份
 - [ ] 三支腳本的 header 版號與 `CHANGELOG.md` 對齊，`config.ttl` 加 `script_version` 並寫進 log 開頭
 - [ ] `docs/TTL_Script_Blanton_Status_*.xlsx` 更新為全 OK，或把剩餘項目移進 Future Extensions
-- [x] 打 git tag，push `nas` + `gitea`（已至 `V1.2.3`；`publish/` 依 Script A 檔頭版號打包）
+- [x] 打 git tag，push `nas` + `gitea`（已至 `V1.2.4`；`publish/` 依 Script A 檔頭版號打包）
 
 **驗收條件：** 從 zip 解壓到一台乾淨的測試 NB，照 README 操作，不看原始碼就能完成一輪 A→B→C
 並產出 summary；`publish/` 內容與 git tag 一致。
diff --git a/CLAUDE.md b/CLAUDE.md
index 5e18939..6d9a707 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -9,7 +9,7 @@ DUT 端的取數能力由一組 **bash 工具庫** 提供（CB FPGA `pcimem` →
 
 完整架構見 [ARCHITECTURE.md](ARCHITECTURE.md)。
 
-**目前狀態（2026-09-23）**：Script A 為 **V1.2.3**（A 集中記錄所有 TTL 的變更）。涵蓋
+**目前狀態（2026-10-01）**：Script A 為 **V1.2.4**（A 集中記錄所有 TTL 的變更）。涵蓋
 PCIe AER / DDR EDAC / PMON+TPM / 電壓 margin（9 顆 LTC2980）/ SWB loopback 線速流量 /
 10G+1G 管理網路 ping / BMC DDR 與 USB / NVMe 健康，壓力層走平台的 `bgctl`。
 switch unit 數量由 `config.ttl` 的 `SWB_UNIT0` / `SWB_UNIT1` 宣告，風扇轉速由 `FAN_SPEED` 指定
@@ -36,11 +36,14 @@ NFC tag 讀取由 `nfc_polling.sh` 背景輪詢（A 做基線、B 起、C 停並
 取 PMON + 兩片 SWB 的軌功耗 + **AMD CPU 封裝功耗**（`avt_pmpower.sh`，V1.2.3）；**沒有收尾段**，中斷後要手動 `blanton_tr518.sh stop`）。
 **V1.2.3 起 PMON 快照（`utils/setup_pmon.ttl`）多了 DDR5 DIMM 溫度（`ddr5_temp.sh`）與 LTC4287 HSC 溫度
 （`hsc_temp_readback.sh`）**，A/B/C/4/5 全部吃到；HSC 那支每次約 +4 秒。
+**V1.2.4 新增 Tray ID I2C stress（`tray_id_stress.sh`）**：Script A 跑一次當基線、Script B 每輪 soak 跑一次。
+另新增 **`6_Blanton_Script_BER_Cycle.ttl`**（Diag ↔ SONiC 冷開機循環量 BER，**獨立跑不接 A→B→C**），
+操作與分析見 `tmp/BER_Test_Cycle/runbook.md`（tmp 不進 git）。
 以及 **`5_Blanton_Script_Boot_Cycle.ttl`**（重開機循環，**獨立跑不接 A→B→C**：登入 → 風扇 →
 Check Pt1~Pt13 → `reboot` → `wait "Booting in blind mode"`，`cnt_cycle` 每輪遞增，`while 1` 無止境，
 要停就關 Tera Term 的 macro）。**尚未上機驗證**。
 流程圖：`docs/Blanton_Test_Flow.drawio`。
-最後一次發布是 **V1.2.3**；SWB 的 I2C 通道與位址已於 2026-08-19 上機驗證。
+最後一次發布是 **V1.2.4**；SWB 的 I2C 通道與位址已於 2026-08-19 上機驗證。
 margin 的 `VNOM` 已於 2026-08-30 改為 Blanton 實測中位數（144 條軌中 86 條上調 0.8~2.5%）。
 交付用 `./publish/publish.sh` 打包。
 
@@ -140,6 +143,12 @@ bash ~/Blanton_Script/port_prbs_monitor.sh stop         # 收尾會跑 prbsstat
 #   ⚠️ AVT 是 NDA，不在交付包裡：DUT 上要先解壓到 ~/AVT_Linux_NDA_2.8.37/，沒有就每輪 exit 2
 #   ⚠️ 數值是 SMU telemetry 不是量測，要準就對照 VR 的 PMBus READ_POUT
 
+# ── Tray ID I2C stress（V1.2.4，Script A / B 已接）────
+~/Blanton_Script/tray_id_stress.sh            # bus 34/35/38/39，0x70 reg 0x02：寫 0xA5/0x5A 讀回比對 → Summary
+~/Blanton_Script/tray_id_stress.sh -n 100     # 重複 100 輪
+~/Blanton_Script/tray_id_stress.sh -R         # 跑完不還原（預設會寫回原值並讀回確認）
+#   exit 0 = 全 PASS、1 = 有 FAIL（讀回不符）或 ERROR（i2cset/i2cget 本身失敗）、2 = 參數錯
+
 # ── PDB / CPB power brick 讀值 ──────────────────────
 ./Blanton_Script/pwr_brick.sh show         # Vin/Iin/Vout/Iout/Temp × 5 顆
 ./Blanton_Script/pwr_brick.sh show -r      # 多印 raw word
@@ -357,6 +366,11 @@ Tera Term 連 COM port (115200-8-N-1)
 - ⚠️ **`stress_hhmd.py` / `stress_pcie.py` 已於 2026-08-17 由 KC 移除**（Status 表 ScriptB #5/#7）。
   Script B 現在是 **8 個背景 job**（1 mlucas + 5 mem + ssd + usb），不是 10 個。
   I2C／PCIe 的持續讀取壓力目前沒有替代品。
+- ⚠️ **`prbsstat Ber` 要等第一個 interval 結算之後才讀：sleep 必須「大於」Interval**（2026-09-30 驗證）。
+  `6_Blanton_Script_BER_Cycle.ttl` 用 `Interval=30` + `sleep 40`。拿同一輪 `prbs get` 的錯誤數交叉比對：sleep 10 時 Diag 低 ~60×、
+  SONiC 低 ~40×；sleep 30（= Interval）時 Diag 仍低 ~60×（Ber 在 STArt 後 30.15 s 送出，剛好在結算前）。
+  ⚠️ **Script A / C 的 BER 也是 `blanton_ber.sh start`（Interval=30）→ TTL `sleep 30` → `report`**，跑在 SONiC 上 —— 正是「sleep = Interval」的邊界情況，
+  能不能趕上第一個 interval 結算**未驗證**。建議改成 `sleep 40`（或 `BER_INTERVAL` 調小），並用 `validate_prbsget.py` 的方法驗證一次
 - ⚠️ **`pause` 是停 macro，`sleep` 是停 DUT**（V1.2.0 起 A/B/C 一律用後者）：`pause N` 期間 macro 不理會
   DUT，shell 是閒著的，等於用猜的估上一個指令跑多久；`sendln "sleep N"` + `wait prompt_sonic_root`
   把等待放到 DUT 上，prompt 回來才繼續，兩邊不會走散，而且這一段會帶時戳進 log。
diff --git a/docs/release-notes/v1.2.4.md b/docs/release-notes/v1.2.4.md
new file mode 100644
index 0000000..58cd5fc
--- /dev/null
+++ b/docs/release-notes/v1.2.4.md
@@ -0,0 +1,54 @@
+# v1.2.4 — Tray ID I2C stress in Script A and B, and a Diag / SONiC BER cycle that reads the BER correctly
+
+## ✨ New features
+
+**`tray_id_stress.sh` — Tray ID I2C write / read-back stress**
+* Buses `34` / `35` / `38` / `39`, device `0x70`, register `0x02`. Each bus gets `0xA5` written and read back, then `0x5A` written and read back — the two patterns put every bit in both states.
+* One line per step (`PASS` / `FAIL` / `ERROR`), then a per-bus **Summary** table and a single `Tray ID stress RESULT: PASS|FAIL` line. Exit `0` = all PASS, `1` = any FAIL or I2C error, `2` = bad arguments.
+* `FAIL` (the read worked but returned the wrong value) and `ERROR` (`i2cset` / `i2cget` itself failed) are counted separately, because they point at different faults.
+* The original register value is read first and **written back at the end**, verified by a read. `-R` skips that; `-n N` repeats the whole sequence N times. Buses, address, register and patterns are editable at the top of the file.
+
+**Script A and Script B run it**
+* **Script A** runs one pass after `show_dmesg` as the baseline.
+* **Script B** runs one pass in every soak round, before `sleep 60` — 12 writes per round, registers restored each time.
+
+**`6_Blanton_Script_BER_Cycle.ttl` — Diag ↔ SONiC BER cycle (standalone)**
+* Each cycle measures PRBS BER on unit 0 in the Diag OS, cold-boots into SONiC, measures again, and cold-boots back to Diag. `while 1`, no end. The boot target is picked in the BIOS Boot Manager (`USB Device` = Diag, `Hard Drive` = SONiC).
+* Log: `Logs\Blanton_BER_Cycle_<ts>.log`, timestamps always on.
+
+## 🐛 Bug fixes
+
+**`prbsstat Ber` was read before the first interval had been published — BER read 40–60× low**
+* The BER cycle originally read `prbsstat Ber` 10 s after `prbsstat STArt Interval=30`. Checked against the error counts that `prbs get` reports in the same cycle, that read **Diag ~60× low and SONiC ~40× low**.
+* Moving to `sleep 30` (equal to the interval) fixed SONiC but **not Diag**: its `Ber` goes out 30.15 s after `STArt`, just before the first interval is published. SONiC's `bcmcmd` adds ~0.3 s and just makes it.
+* The macro now uses **`Interval=30` + `sleep 40`**. Over 73 cycles both sides agree with the `prbs get` estimate to within 0.1 decade. The rule: **the sleep must be longer than the interval.**
+
+## 📦 Downloads
+
+| File | Contents |
+|---|---|
+| `Script_ABC_Blanton_V1.2.4.zip` | The full Tera Term working directory, including `Blanton_Script/` to copy onto the DUT |
+
+```bash
+chmod +x ~/Blanton_Script/*.sh
+grep -rlU $'\r' ~/Blanton_Script    # expect no output
+```
+
+## ⚠️ Before you run
+
+* **`chmod +x` after deploying.** Script A and B call `tray_id_stress.sh` by path; without the exec bit every call is `Permission denied` and the round carries on without the check.
+* **Any BER log taken before 2026-09-30 14:13 reads 40–60× low** (BER cycle with `sleep ≤ Interval`). Relative Diag-vs-SONiC trends are usable; absolute values are not.
+* **Script A / C's BER is the same edge case**: `blanton_ber.sh start` (Interval=30) → `sleep 30` → `report`, on SONiC. Whether it catches the first interval has **not been verified**. Lengthening that sleep to 40 is the safe change.
+* **The BER cycle's SONiC → Diag boot writes a hard-coded BDF** (`pcimem /sys/bus/pci/devices/0000:05:00.0/resource0 0x480`). Check the CB FPGA BDF on every unit before running it.
+* **The BER cycle expects the hostname `sonic`.** A unit with another hostname (e.g. `Margin02`) needs `prompt_sonic` / `prompt_sonic_root` edited, or the macro waits forever.
+* **The BER cycle sets the fan to 30 % on the SONiC side only** — SONiC runs ~11 °C hotter than Diag, a variable in any Diag-vs-SONiC comparison.
+* **Its SONiC password is the `YourPaSsWoRd` placeholder**, and it does not read `config.ttl` or `secret/`.
+* **Script 4 has no teardown**: finish it with `blanton_tr518.sh stop` **and** `systemctl stop mlucas-amm`.
+* **`FAN_SPEED` is 100.**
+
+## 🔗 Links
+
+* [ARCHITECTURE.md](https://etgit.et-wen.com/etwen/Blanton_TTL_Script/src/branch/main/ARCHITECTURE.md) — test flow, data models, constraints
+* [CLAUDE.md](https://etgit.et-wen.com/etwen/Blanton_TTL_Script/src/branch/main/CLAUDE.md) — commands and the bench gotchas
+
+**Full changelog:** [V1.2.3...V1.2.4](https://etgit.et-wen.com/etwen/Blanton_TTL_Script/compare/V1.2.3...V1.2.4)
diff --git a/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl b/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl
index d755c0e..7a7a972 100644
--- a/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl
+++ b/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl
@@ -1,7 +1,7 @@
 ; =============================================================================
 ; Script A for Blanton
-; Version : V1.2.3
-; Date    : 2026-09-23
+; Version : V1.2.4
+; Date    : 2026-10-01
 ; Author  : ETWen
 ; =============================================================================
 ; Version History:
@@ -740,6 +740,60 @@
 ;                                                                         !! without -q the full PM table is printed every round, and
 ;                                                                            Script 4 loops once a minute - the log grows by one full
 ;                                                                            table per minute
+;   V1.2.4  2026-10-01  Blanton_Script/tray_id_stress.sh                Created v1.0.0 - Tray ID I2C write / read-back stress
+;                                                                         Buses 34 / 35 / 38 / 39, device 0x70, register 0x02. Each
+;                                                                         bus: write 0xA5, read back, compare; write 0x5A, read back,
+;                                                                         compare - the two patterns put every bit in both states
+;                                                                         One line per step (PASS / FAIL / ERROR), then a per-bus
+;                                                                         Summary table and 'Tray ID stress RESULT: PASS|FAIL'
+;                                                                         Exit 0 = all PASS, 1 = any FAIL or I2C error, 2 = usage
+;                                                                         -n N repeats the sequence N times; buses / addr / reg /
+;                                                                         patterns are editable at the top of the file
+;                                                                         The original value is read first and written back at the
+;                                                                         end (verified by a read). -R leaves the register at 0x5A
+;                                                                         !! FAIL = the read worked but returned the wrong value;
+;                                                                            ERROR = i2cset / i2cget itself failed. They are counted
+;                                                                            apart because they point at different faults
+;                                                                         !! a bus whose original value cannot be read is NOT
+;                                                                            restored (there is nothing to restore to) - the line
+;                                                                            says so
+;                                                                         !! called by path, so it needs the exec bit on the DUT:
+;                                                                            chmod +x ~/Blanton_Script/*.sh
+;                       ScriptA                                         Add Tray ID stress after show_dmesg (one pass, baseline)
+;                       ScriptB                                         Add Tray ID stress to every soak round, before sleep 60
+;                                                                         Each round now writes 0xA5 / 0x5A to four Tray ID
+;                                                                         registers and restores them - 12 writes per round
+;                       6_Blanton_Script_BER_Cycle.ttl                  Added - Diag / SONiC BER cycle, a STANDALONE macro (not A/B/C)
+;                                                                         Each cycle: PRBS BER on unit 0 in the Diag OS, cold boot
+;                                                                         into SONiC, the same PRBS BER again, cold boot back to
+;                                                                         Diag; while 1, no end. Boot selection drives the BIOS
+;                                                                         Boot Manager ('USB Device' = Diag, 'Hard Drive' = SONiC)
+;                                                                         Log: Logs\Blanton_BER_Cycle_<ts>.log, timestamps always on
+;                                                                         Report tools (not shipped): tmp/BER_Test_Cycle/
+;                                                                         parse_multi.py, gen_multi_html.py, validate_prbsget.py
+;                                                                         prbsstat STArt Interval=30, then sleep 40, then Ber
+;                                                                         !! the sleep MUST be longer than the Interval. Checked
+;                                                                            against the error counts that 'prbs get' reports in the
+;                                                                            same cycle: with sleep 10 Diag read ~60x low and SONiC
+;                                                                            ~40x low; with sleep 30 (= Interval) Diag was still
+;                                                                            ~60x low - its Ber is sent 30.15 s after STArt, just
+;                                                                            before the first interval is published. Interval=30 +
+;                                                                            sleep 40 matched on both sides over 73 cycles. Every
+;                                                                            BER log taken before 2026-09-30 14:13 is low by 40-60x
+;                                                                         !! SONiC -> Diag cold boot writes pcimem
+;                                                                            /sys/bus/pci/devices/0000:05:00.0/resource0 0x480 with a
+;                                                                            hard-coded BDF (the Diag side uses fpga_switch.sh, which
+;                                                                            finds the FPGA itself). Check the BDF on every unit
+;                                                                         !! the SONiC password is the YourPaSsWoRd placeholder and
+;                                                                            the macro does not include config.ttl or secret/
+;                                                                         !! prompt_sonic_root is 'root@sonic:~#'. A unit whose
+;                                                                            hostname is not 'sonic' (M02 = Margin02) needs the
+;                                                                            prompts edited or the macro waits forever
+;                                                                         !! fan-speed-control.sh 30 is set on the SONiC side only;
+;                                                                            SONiC runs ~11 C hotter than Diag, a variable in any
+;                                                                            Diag vs SONiC comparison
+;                                                                         !! measures unit 0 only, port 268 not in the list, yet
+;                                                                            wait_init still waits for BOTH units (SWB_UNIT0/1 = 1)
 ; =============================================================================
 include "config.ttl"