Isaac Marino Bavaresco wrote: > How can the boot-loader tell if a block full of 0xff was present in > the middle of the application? Um, by checking it. However, does it really matter? A whole block set to the erased value in the middle of the app image is going to be rare, since the linker starts filling program memory from the beginning, generally without leaving gaps. If bootload speed is really critical and your app is expected to have large tables often set to the erased value, then checking for a whole block set t= o all 1s might make sense. If these conditions are not met, there is little advantage and the extra code just adds extra risk of a bug. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .