If my understanding is correct, if you update the system menu with hiyaCFW, it'll replace the modified 1.4 Launcher with the unpatched 1.4.5 (or 1.4.6) Launcher, making hiyaCFW unusable.
So, I think a good way to mitigate this issue would be to check if Launcher's header CRC is equal to that of any of the 1.4.5 Launchers (as opposed to checking if it matches the modified 1.4 Launcher, so that I and no one else people can use customized Launchers as if wish) and display an error if this is the case.
If my understanding is correct, if you update the system menu with hiyaCFW, it'll replace the modified 1.4 Launcher with the unpatched 1.4.5 (or 1.4.6) Launcher, making hiyaCFW unusable.
So, I think a good way to mitigate this issue would be to check if Launcher's header CRC is equal to that of any of the 1.4.5 Launchers (as opposed to checking if it matches the modified 1.4 Launcher, so that
I and no one elsepeople can use customized Launchers as if wish) and display an error if this is the case.