I guess you could uninstall, then reinstall and don't install TSH stuff, just fly the stock game. TSH added the iraq theater which my guess is required landpal file modifications.
Here is the readme file which describes each landpal file.
Note that file 38 makes the ncape theater desert brown, if you have added it. I use it for many missions over Libya, Somalia, etc.
readme_terrain
This file is a list of all landpXX.pcx files compatible with the TSHv3 unified landpal format. XX is a number between 01 and 99. Please update and distribute this file with all landpals developed with the TSHv3 unified format.
1. Early spring: early spring season with remains of winter snow
2. Spring: more vivid colors than early spring, little or no snow
3. Summer: colorful summer terrain
4. Autumn: subdued autumn colors
5. Late Autumn: same as autumn but with more snow
6. Winter: snow coverage greatly increased (primarily in Ncape) while general colors more washed out
7. Deep Winter: in Ncape, almost 100% snow coverage over land; in iraq, same as "Winter"
8. TSHv3 default terrain
9. Early spring dark: early spring with darker mood
10. Spring dark: spring with darker mood
11. Summer dark: summer with darker mood
12. Autumn dark: autumn with darker mood
13. Late autumn dark: late autumn with darker mood
14. Winter dark: winter with darker mood
15. TSHv3 default terrain with darker mood
16. Inverted spring: desert in North Cape & spting vegetation in Iraq
17. Inverted summer: desert in North Cape & summer vegetation in Iraq
18. Inverted autumn: desert in North Cape & autumn vegetation in Iraq
19. Diversity: vegetation and sand/stone in both theatres
20. TSHv3 default terrain vivid: similar to default but with fuller and richer colors
21. Stone: predominantly stone-like colors
22. Stone vivid: predominantly stone-like colors but with fuller and richer colors
23. Rock: simulates rocky terrain similar to old rock terrain made by Pretzel
24. Dirt: mostly brown colors simulating muddy terrain
25. Terra Balkans: similar to Blitz’s old Balkans theater but with lighter and more diverse colors
26. Terra Balkans Old: similar to Blitz’s old Balkans theater
27. Terra Batlic: similar to Blitz’s old Baltic theater but with lighter and more diverse colors
28. Terra Batlic old: similar to Blitz’s old Baltic theater
29. Terra NorthCape: similar to Blitz’s old terra NorthCape theater but with lighter and more diverse colors
30. Terra NorthCape old: similar to Blitz’s old terra NorthCape theater
31. Terra kola: similar to Blitz’s old terra kola theater
32. B&W: black and white terrain
33. Mars: Mars-like red color terrain
34. Europe spring: Europe in spring, Iraq terrain similar to Rock terrain
35. Europe summer: Europe in summer. Iraq terrain similar to Rock terrain
36. Europe autumn: Europe in autumn. Iraq terrain similar to Rock terrain
37. Europe winter: Europe in winter. Iraq terrain similar to Rock terrain