I have following problem: I just installed Arduino IDE 1.6.10, replacing my previous 1.6.4
In the former one I changed the boards.txt to allow an Arduino Mini to have more code space, since the same Atmega is used as in the Nano (except for the power saving design). It worked fine.
I wanted to do the same trick in the new installation. I open the file with texteditor (WIN10), change the value, I save. Afterwards I get upon compile an error which complains about formatting of the file and does not let me compile anything (not even for other boards). Replacing the file with the original from the installation package solves the issue, but I need to change it. Reason is simple, all the breadboards I use for debugging have Atmega328 on them, and not Atmega328P (I could get the former with bootloader already installed). I tried to bootload them as Nano but the non-P variant does not let me. So I need to make this trick and my sketch needs more space than the Mini defines for code, Nano has enough.
Protonerd:
I get upon compile an error which complains about formatting of the file
Please post the error message.
Please post your modified boards.txt file. Probably in the text of the message using code tags is best, though there's a chance the issue is caused by the way the text editor formats the file so go ahead and attach it as well just in case that will be useful.
Changing the boards.txt to tell it that the chip has more code space does not make it so. The reason some of the ATMega328p boards have less code space than others (by a little) is that they use a bootloader that takes up more space - so if you want to get the last bit of code space out of your '328p boards, you need to burn a new bootloader to them using an ISP programmer, otherwise as soon as you try to use that extra space, the bootloader will refuse to write it.
You don't need to modify boards.txt, either. You want to burn the Uno bootloader - that one is only 512 bytes, and uploads faster; it's the best of them. Just connect your ISP programmer, tell it the board is an Uno, and do burn bootloader; therafter, tell the board it's an Uno. I bootload all my '328p-based boards as Unos.
If you want to use a board without a bootloader, then you would need to either modify boards.txt or install a custom hardware package that already has such a board definition (I think mcudude/hansibull's MiniCore has definitions for no-bootloader atmega x8 series chips)
Thanks for the hint. Actually pert already gave me the hint about the Uno bootloader, I tried it a while back and it worked, I'm just a bit cautious to use it on all my boards yet, having more experience with the Nano bootloader.
You are not fully right saying that the trick with overwriting the boards.txt will not work. As I mentioned earlier I already made it work, it's just that with the new IDE 1.6.10 I deleted my old installation of 1.6.4 (silly idea), and now if I change the file the IDE will refuse to upload. Once I can reproduce I will provide a test case with the boards.txt and the exact error message.
The motivation I want to do that is, that usually I burn my boards with Nano bootloader (DIYino), but I do not have any of them. What I'm left now at home with are two older DIYino boards, where I had had Atmega328 (without the P) chips with pre-burned bootloader mounted. They have the Mini bootloader -> ~2kBytes less code space. But in fact if I change the boards.txt these guys will accept code with more than allowed for Mini.
You can ask why I simply do not re-burn another bootloader to them. I attempted it, but the Atmega328 did no accept it...? Why, I have no clue... maybe I give it a new try. Maybe the bootloader will recognize it's an Atmega328 and not a 328P and will quit?