Antminer S19 – Kernel Panic After OC

Hard power-cycle at the breaker for 30 seconds, then boot. Not a soft reboot — a cold start. Clears wedged driver state in RAM and gives NVRAM a clean read on the next boot. A one-shot panic from a transient can end here.

Clear the OC profile with the Reset button. Power on, wait 2 minutes, hold Reset for 5 seconds, wait 4 minutes for auto-restart (Bitmain doc https://support.bitmain.com/hc/en-us/articles/115003595387 — valid only within the 2-10 min post-boot window). If the miner now runs clean at stock, your OC was past silicon lottery — rebuild it slowly in Tier 2.

Verify ambient temperature at the intake grille — not room-middle — is ≤ 35 °C. High ambient plus aggressive OC is the single most common panic recipe because the tuner's V-F table assumes a colder die than most home setups actually run.

Verify the PSU cord and PDU are correct for your model. S21 uses a new P13 20 A cord; using an undersized S19 cord on an S21 or a damaged cord on an S19 produces voltage sag that mimics undervolt-induced panics. Use the cord the miner shipped with.

Do not hot-swap the PSU with the PDU live. Plugging or unplugging a live miner kills PSUs and produces random-reboot symptoms (Bitmain doc https://support.bitmain.com/hc/en-us/articles/360001836994). Power down the PDU before touching any connector.

Rebuild the OC from stock, slowly. Start at nameplate (110 TH/s @ 3250 W for base S19), add +50 MHz per step — half the usual community default — and wait 15 minutes between steps. If HW% climbs over 1.5% or the miner reboots, back off 100 MHz and stop. That is this miner's silicon-lottery ceiling. It varies per chip.

Measure PSU output at the board connector under full load. Expect ≥ 13.8 V sustained on a standard S19. Below that means PSU tired or circuit undersized. Swap PSU with a known-good unit before suspecting the hashboard or firmware.

Measure line voltage at the panel under load. 240 V split-phase should be 235-245 V; 208 V commercial should be 202-212 V. If you're on 110 V and you have an S19, you already have your answer — see antminer-s19-110v-insufficient-power. Low line = more PSU current draw = more sag = panic.

Re-seat every hashboard power and data cable. Power off at the breaker. Disconnect each connector, inspect for blackening, bent pins, or corrosion, reconnect firmly — listen for the click. A cable that is almost seated produces intermittent voltage on one domain, which panics the init path.

Replace the CR2032 RTC battery on the control board. A dead battery fails TLS cert expiry checks during pool auth; on some firmwares this cascades to a service crash that panics the kernel. $2 fix, 5-minute job; replace on any S19 more than 2 years old that has started acting weird.

Roll Bitmain firmware one version back or forward within your hardware revision only. Find the revision on the control-board sticker (BHB42 / BHB56902 etc). Newer Bitmain FW is cryptographically signed — flashing a wrong-revision image bricks the control board because an interrupted downgrade is not recoverable from the web UI.

SD-card recovery when the Reset button will not clear the profile. Use a 16 GB or smaller Micro SD, FAT32, stock firmware from service.bitmain.com/support/download, flashed with Etcher. Insert into the control board, power on, watch for the recovery LED sequence (3-5 minutes), power off, remove card, power on normally. Overwrites overlayfs and kills a corrupted OC profile that survived factory reset.

Cross-flash DCENT_OS — D-Central's own open-source Antminer firmware. Per-chip HW%, closed-loop autotuning (steps up and observes per chip rather than trusting an open-loop V-F table), stratum v2, no licensing fees, open-source. Alternatives: Braiins OS+, LuxOS, Vnish. Note: custom firmware voids Bitmain warranty — non-issue on out-of-warranty units.

Stop the stock autotuner. Bitmain acknowledges autotune can crash on specific chip bins (https://support.bitmain.com/hc/en-us/articles/18237912339097). Set a fixed manual profile at a conservative frequency (e.g. 525-560 MHz depending on silicon) at stock voltage and run 24 hours before touching tuning again.

Use DCENT_OS or Braiins OS+ per-domain voltage autotune. Braiins documents 10-15% efficiency gains vs stock and 38-45% power savings at 80 TH/s underclock (https://braiins.com/blog/smarter-clock-speed-management-for-bitcoin-miners-maximize-roi-minimize-waste). Per-domain tuning avoids single-domain collapse that causes most post-OC panics.

Isolate the suspect hashboard. Power off, label slots 0/1/2 with tape, pull one hashboard at a time, boot. If panic stops when a specific board is pulled, that board is the source. Re-seat its connectors and retest. If panic returns with the board reinstalled, the board owns the problem — see antminer-s19-hashboard-init-failure.

Stop DIY and book a D-Central repair when: SD recovery + DCENT_OS/Braiins OS+ still panics within 30 minutes of chip init; OR all three hashboards pulled and the control board still panics at boot (Amlogic A113D / eMMC); OR visible cap bulging, MLCC cracking, or burnt smell on any board; OR a downgrade got interrupted on a signed build (soft-brick, JTAG-recoverable only). https://d-central.tech/services/asic-repair/ · turnaround 5-10 business days.

Ship safely. Hashboards in anti-static bags, double-boxed with ≥ 5 cm foam each side. Include a note: observed symptoms, firmware version at the time of panic, the OC profile that triggered it (frequency + voltage + tuning target), last-known-good configuration, and your contact info. This saves us diagnostic time and saves you money.