How to Make Elytra Trims Show Correctly with Resource Packs
Why trims can look wrong
The mod is designed so trims are customizable through resource packs. If your trimmed elytra shows a flat color, a missing texture, or the trim does not appear at all, the resource pack you are using likely does not include elytra trim textures, or it is overriding the mod's assets.
Fixing the display
1. Check that the resource pack you have selected actually supports elytra trims. Packs made only for vanilla armor trims may not include the elytra variants.
2. Move the elytra-trim-supporting pack above any pack that overrides armor or elytra textures in your resource pack list.
3. Reload resources with the in-game reload option (or reopen the world) after changing pack order.
4. If trims still do not render, temporarily disable other packs to confirm the conflict, then re-enable them one at a time.
Multiplayer note
On a server, the trim data is stored on the item, but each player sees it through their own resource packs. Two players with different packs can see the same elytra rendered differently. If a trim looks absent for a friend, it is almost always their pack, not the item.