init: F3 unlock project — ESP32-C3 bridge + procedure for CLAR200 Exos X18

2026-06-14 21:12:56 -04:00
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+# IDEA.md — Project Idea
+
+## What is this?
+
+A procedure + ESP32-C3 firmware to talk to the **Seagate F3 diagnostic serial
+terminal** on two EMC/CLARiiON-locked Seagate Exos X18 SAS drives
+(ST16000NM004J, EMC firmware ES2264), in order to reformat them out of the
+locked "SS160520 CLAR200" state and back into usable 512-byte-sector drives
+for the `tank` ZFS pool.
+
+The two drives (SN **ZRS015V7**, **ZR511KWK**) were bought from ServerPartDeals
+already pulled from an EMC array and never properly decommissioned. They answer
+SCSI INQUIRY/VPD but return `Hardware Error / Internal target failure (44h/00h)`
+to every other command — including READ CAPACITY — so **no host-side software
+(sg_format, openSeaChest, SeaChest, firmware download) can touch them.** That is
+fully documented in `~/bin/EMC_CLAR200_DRIVE_FIX_NOTES.md`.
+
+The only remaining DIY lever is the drive's **F3 service terminal**, an
+out-of-band UART on the PCB that bypasses the SCSI command layer entirely. This
+project builds the cable (an ESP32-C3 acting as a 3.3 V USB-serial bridge) and
+documents the F3 procedure to attempt the unlock.
+
+## Problem it solves
+
+- `tank` is short on **14.6 TB+** spare disks: mirror-35 has a dead + a dying
+  leg, and ex-mirror-38 is a bare single-disk vdev. Both need 14.6 TB disks.
+- These two CLAR200 drives are 16 TB and would fix both holes — *if* they can be
+  unlocked. Otherwise they're paperweights / RMA candidates.
+
+## Constraints / preferences
+
+- **Cable:** ESP32-C3 already attached to steel141 at `/dev/ttyACM0`
+  (native USB-Serial-JTAG, MAC `58:8c:81:ac:f0:4c`). 3.3 V logic — native match
+  for the F3 header. No separate USB-TTL adapter needed.
+- **Drive location:** ZRS015V7 currently in a JBOD on pve173. F3 work must be
+  done **on a bench**, not in-chassis — never risk the live 549 TB tank.
+- **Honesty:** Exos-X18 F3 dialect ≠ the well-documented 7200.11 era. The
+  procedure discovers commands via the drive's own `?` help; it does not blindly
+  fire format commands copied from old forums.
+- **Fallback if F3 fails:** RMA to ServerPartDeals (sold not-decommissioned),
+  or decommission in a real EMC VNX array, or PC-3000 SAS.