In order to make the changes, there are a few things you need.
A good Hex editor, such as Hexed. You can download a copy of Hexed from here at FrontierAstro
The main FFE exe file. I would recommend downloading shareware FFE and then downloading
JJFFE but other versions exist.
Knowledge of how to edit exe files with your hex editor.
The most important thing is to make a back-up of your original exe file, whichever you decide to use.
I cannot be held responsible if you ruin your only copy of the program, or otherwise affect your computer, by editing the code incorrectly - you make these modifications at your own risk.
Having said that, if you follow these instructions carefully, and *MAKE A BACK-UP* you'll be fine
1 Run your hex editor and select the exe file for editing
2 Use the search function to locate the following hexadecimal byte stream - D8 18 00 00 50 68 81 (don't include the spaces, they're here for clarity). This sequence should only occur once in the entire exe file, so you'll know when you've found it. It should be the same sequence irrespective of which version of the exe file you're using.
3 Change the last value - 81 - to one of the following:
7D - living planet
7E - living planet
7F - ice planet
80 - living planet
81 - the brown smudge you've already got
82 - living planet
83 - brown planet
84 - brown planet
85 - living planet
86 - living planet
4 Save the changes, exit your editor and run the exe file. With any luck, Earth should now appear in the game as a proper planet according to the value you input. If nothing changes, or the program crashes, then you probably edited the file incorrectly. Restore your original version and try again.