SHA256 miner troubleshooting: CPU, GPU, USB, FPGA & ASIC (SHA256d)

Most “miner problems” fall into a small set of root causes: the miner can’t reach the pool, the miner is reaching the pool but submitting stales/rejects, or the miner is unstable because of power, cooling, drivers, or firmware/client settings. This hub links to practical guides by miner type and shows where we can jump in to resolve issues quickly.

Choose your miner type

Pick the guide that matches your hardware/software. Even if your setup is “weird” (older gear, custom firmware, a proxy in the middle), start with the closest category—you’ll still get the right diagnostic flow.

Fast diagnosis checklist (works for every miner)

1. Confirm the endpoint: the pool’s Stratum hostname + port, and whether it’s TCP or SSL.
2. Confirm identity format: wallet/user + worker name. (Wrong format is the #1 silent failure.)
3. Verify accepted shares: don’t trust local hashrate; watch accepted shares for 15–30 minutes.
4. Compare latency: high ping or packet loss produces stales. If you have multiple locations, compare them.
5. Check power + thermals: undervoltage and heat cause reboots, throttling, and intermittent disconnects.
6. Capture logs: miner logs + pool-side connection logs usually reveal the root cause within minutes.

If you want a clean baseline first, read our Bitcoin miner setup guide and keep a copy of your pool endpoints from the pool URL list.

Miner-side vs pool-side: what we fix

Some problems are on the miner (drivers, firmware, clocks), but many “miner issues” are actually caused by pool-side misconfiguration: unstable Stratum sessions, noisy difficulty updates, inconsistent job cadence, or unclear onboarding docs.

• Miner-side: client/firmware configuration, stability, power/cooling checks, safe tuning, and repeatable testing.
• Pool-side: Stratum behavior, vardiff strategy, failover design, onboarding docs, and monitoring for dropouts.

If you operate a pool and want fewer support tickets, we can also harden your stack—see pool build & setup services and our reliability & security approach.

When to contact us

Reach out if you’re stuck, or if you want the fastest route to a stable, low-reject setup. We’re particularly useful when the problem isn’t “one obvious thing,” but a mix of network conditions, tuning, and pool behavior.

• Miners connect, but accepted shares are near zero.
• Rejects/stales spike after a firmware update, pool change, or hashrate increase.
• ASICs show board dropouts, high HW errors, or random restarts under load.
• You need a repeatable onboarding playbook for customers/farm clients.