- Non-push opcodes in unlocking scripts (scriptSig) • Aft…

79b · February 13, 2026

- Non-push opcodes in unlocking scripts (scriptSig)
• After BSV’s 2020 Genesis upgrade, there is a consensus rule that unlocking scripts may only contain PUSHDATA operations. This makes transactions that put functional opcodes (e.g., OP_TRUE, OP_IF, OP_ADD) directly in the unlocking script invalid today on BSV — even though such constructs were valid (albeit often non-standard for relay) in 2009–2010. Source (see “PUSHDATA Only in Unlocking Script Consensus Rule”): https://wiki.bitcoinsv.io/index.php/Genesis_upgrade
• Concretely: An unlocking script that uses OP_TRUE instead of pushing a true byte, or that performs computations with opcodes instead of pushing precomputed data, would be invalid on BSV today if mined post‑Genesis.