If one wishes to put code and code-related constants like strings in area A of flash, and large amounts of text like HTML in area B of flash, are the following correct?
1) Using an ISP or JTAG must always erase all of flash, e.g,. A and B?
2) The ISP process could do a partial erase, e.g., the ISP device itself is programmed. Maybe not so JTAG? Maybe they just use use a hardware level chip erase? I can't remember if AVRs have that, versus the block erase that I know they have.
3) A bootloader could be designed to erase only the blocks that are receiving download data. That is, one could replace A and not erase or affect B? But I don't think bootloaders do that.
I know, one could add a large serial EEP for this.