To clarify your solution is not what that thread says, but it works too. It's very useful info. Thanks!
So for future readers you got two choices:
1. Use the patch offered in the thread linked by Dale Coop on your Everdrive N8. This patch adds Mapper 30 support to your Everdrive. From there on there's no need to change anything else. Your NESMaker games will run on your Everdrive without further modification.
2. Patch your game.nes file instead. Like Smithee explained you download the iNES Header Checker
(link here). Use that tool to change your game.nes file header option to "2 - UnROM PRG 16k swap" on the tool's dropdown list.
Use option 1 if you got an Everdrive N8. Option 2 is useful if you want to run your game.nes on anything else that doesn't support mapper 30 (e.g. Nestopia, Nintendo DS, PSP, Vita, VC Injection, etc.)
smithee said:
Hi, many thanks for the link ( I did search in the forum - apparently not very good)
I found the solution on that thread; just used iNES Header Checker to change mapper to mapper "2 - UnROM PRG 16k swap". Once saved, it ran correctly in Everdrive!
Regards