Critical hotfix. Mandatory for every node
What happened
At 01:34 UTC on 2026-09-02, at the first pruning sample since v1.5.8 shipped, every v1.5.8 node with a pruned datadir stopped at the same time:
thread 'virtual-processor' panicked at consensus/src/pipeline/virtual_processor/utxo_validation.rs:1200:83:
called `Result::unwrap()` on an `Err` value: KeyNotFound(ChainHashByIndex/0000000000000000)
The H12 warm-up snapshot searched the selected chain down to index 0, which a pruned node no longer holds. Archival nodes and v1.5.7 nodes were not affected. A restarted node hits the same panic again, and nodes that made it through only last until the next sample. Network hashrate dropped from ~700 to ~170 MH/s.
The fix
The search now starts at the retained pruning floor, the same floor coinbase verification already uses (26276d5b). The resulting snapshot is identical to the one an archival node builds, so nothing changes for H12.