@ntstaticPlease check if the camera still boots with compatibility check enabled.
Uncomment
BL check_compatin loader/sx430is/entry.S then recompile.
edit:
Based on the camera manuals, Canon has
removed AE/AF/FE lock from SX4xx and SX6xx series cameras, starting with SX420 and SX610. So, one can't really
upgrade from earlier equivalents anymore because the followup model is more crippled than the older...