1. What did you expect to happen?
   This Script to add fuels
   mods.terrafirmacraft.ItemRegistry.registerFuel(<minecraft:blaze_powder>, 1800, 1350, true, false); mods.terrafirmacraft.ItemRegistry.registerFuel(<minecraft:coal_block>, 19800, 1415, true, true); mods.terrafirmacraft.ItemRegistry.registerFuel(<forestry:charcoal>, 16200, 1350, true, true); mods.terrafirmacraft.ItemRegistry.registerFuel(<immersiveengineering:material:6>, 4400, 1500, true, true); mods.terrafirmacraft.ItemRegistry.registerFuel(<immersiveengineering:stone_decoration:3>, 39600, 1500, true, true);
2. What actually happened instead (i.e. what was the bug)
   That list overrode the default Bloomery Fuels. Coal Block, Charcoal Block (Forestry) and Both coke variants (item & Block) are accepted Bloomery Fuels
3. If they would help to explain the issue, include screenshots
   Floating Charcoal

To Reproduce
Attention to detail is important!

1. Do
   Ct ass Bloomery Fuel
2. Then do
   Attempt to use the bloomery with default fuel

Meta Info
-TerraFirmaCraft-MC1.12.2-29.5.120

• Were any other mods included? Can you reproduce it without these other mods?
  Of course lol
• If necessary, what other mods (including versions) MUST be present to experience the bug?
  CraftTweaker2-1.12-4.1.20

So, I just tested this in build 133 and seems to be working as intended (both charcoal and blaze powder were accepted):

ItemRegistry.registerFuel(<minecraft:blaze_powder>, 1800, 1350, true, true);

Should you or anyone else find this bug again feel free to re-open this issue and comment reproduction steps (one buggy crafttweaker script line would be ideal).