heFontMapper makes the normal, low resolution application as a semi-hi-res, silk-foldable application. But some applications cannot affect this: That have no idea for changing fonts from other applecations. Already works on HandEra-HiResolution mode. Cannot run on ScaleToFit mode. Some of them would become scrambled screen, and you sometimes need to do the hardware-reset for the worst of it.So you need to backup all data before testing. Note: The heFontMapper interrupts the internal process of PalmOS, and changes font sizes. So, there are some application that cannot work well with heFontMapper.And I have no assurance for working on the future PalmOSes and applications, too.