Update metadata for fixed-supply spl-token

Question

I've been searching for the answer to this question with no luck.

I have BACH Token, a spl-token that I created two years ago, more or less. I designed it to be a fixed supply of 18 million (it was 18.4 million, then I burned 0.4 a couple of weeks ago) and 12 decimal places.

I realized that Phantom no longer displays the icon due to this issue. It did until it dropped support to the original spl-list repo. So, I tried to find a way to update the metadata. But it seems like it's impossible without the mint authority. As of now, I don't want to create another token.

Is there a way to update the spl-token metadata with a fixed supply, as in a token with no mint authority (the requirement for a fixed-supply token)? This question is not about how to turn a spl-token into a fixed-supply token.

If not, as far as I know, it sounds like a design bug from the Solana team or Metaplex since they implemented the metadata standard. Or what's the logic behind it?

Answer 1

In order to create the metadata, Metaplex's metadata program requires a signature from the mint authority, because they don't want to allow anybody to create the metadata for a token.

When you create token metadata, you can set a different update authority for the metadata, so that you can safely relinquish the mint authority while retaining the ability to update the metadata.

Unfortunately, this means that if your token doesn't already have metadata, and the mint has no mint authority, you cannot create Metaplex metadata for it. The reason: which authority should allow it? There's no authority on the mint for the metadata program to validate.

Answer 2

You can set the mint authority to null. This means there can be no more tokens minted:

In js you can do that like this:

const freezMint = await setAuthority(
  connection,
  keyPair,
  mintkeyPair.publicKey,
  keyPair.publicKey,
  AuthorityType.MintTokens,
  null,
  [keyPair],
  {
    commitment: "confirmed",
  },
  TOKEN_2022_PROGRAM_ID
);