{"type":"rich","version":"1.0","title":"shortwavesurfer2009 wrote","author_name":"shortwavesurfer2009 (npub1ge…ejcs3)","author_url":"https://yabu.me/npub1ge0tzdqy6useekgu9d9g5l3s3t2wpx7p9xxuprz7ajzjaxl4mgyssejcs3","provider_name":"njump","provider_url":"https://yabu.me","html":"I was actually very interested in your question, so I asked it somewhere else and got an answer. The block hashes are hard-coded into the software at each checkpoint, which means that this software will reject any block hashes that do not match. So, not only would you have to do the Proof of work, but you would also have to convince a majority of  node operators to switch to your fork of the software."}