user84445: Let's say I want to rewrite the software behind the hardware of current asics. Would it still mine, for example, sha1 algorithms orders of magnitude faster than a normal cpu would?

user26873: Application Specific Integrated Circuits are hard set to only do one thing, and in the case of bitcoin ASICs, that's SHA256 hashes. You cannot re-write the software, you would need a new circuit built that only does SHA1 or whichever hash you're looking for. 
https://en.wikipedia.org/wiki/Application-specific_integrated_circuit

84445: <p>Let's say I want to rewrite the software behind the hardware of current asics. Would it still mine, for example, sha1 algorithms orders of magnitude faster than a normal cpu would?</p>
 26873: <p>Application Specific Integrated Circuits are hard set to only do one thing, and in the case of bitcoin ASICs, that's SHA256 hashes. You cannot re-write the software, you would need a new circuit built that only does SHA1 or whichever hash you're looking for. </p>

<p><a href="https://en.wikipedia.org/wiki/Application-specific_integrated_circuit" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Application-specific_integrated_circuit</a></p>
