Creating a seed phrase with 253 dice rolls + passphrase with dice rolls.

I have had my Bitcoin stored in an air gapped jade wallet for a few years now. Truly considered a cold card but went with jade. Had a 10 character non-word passphrase, too, so even if I had gone with cold card, I would ultimately have been OK. But I was now paranoid that while jade's RNG for seed generation was allegedly sound, I truly had no way of knowing and for how long?

So I did some research and learned about creating your seed phrase with dice rolls. I didn't like the idea of a 100 dice roll seed phrase because it required converting it with some program which needed to also be on an air gapped system, which I don't have, and also required trusting that program. I decided to just do the 253 dice roll method and it honestly was fairly simple, it just took some time.

I have a lot of D6s from Warhammer and a number of D and D dice sets, so I just did 23 sets of 11 dice rolls. I would roll the 11 d6s, convert them to binary based on evens being 0 and odds being 1. Then converted the 23 11 digit binary numbers to decimal numbers.

Unfortunately, I couldn't find a calculator and didn't want to be plugging these numbers into a phone or computer calculator so I did it all by hand. Then used a bit 39 word list to determine which words each number corresponded to.

Lastly, I created a 12 character, non-word, case sensitive passphrase which included symbols. To do this with dice, I associated numbers, lower case, upper case, and symbols with 1-4. For each character, I rolled a D4 to determine what that character would be. For numbers, I rolled a D10. For letters, I rolled 3 D10s and subtracted 4. If I happened to roll a 3 or 4 I planned to just reroll, but that didn't actually happen. And for the symbols (there's 33 acceptable in BIP39,) I ordered them out, then rolled 3 D12s and subtracted 3. I planned to reroll if I rolled a 3.

I am not sure if this passphrase method is truly good, but it was the best I could come up with that I thought would be truly random.

All in all, it only took a few hours and was actually pretty fun. Would have been quicker if I still had a regular calculator like my ti85 from college, lol. Oh well.

Imported the seed phrase into my jade, picked a random 24th word by rolling a D8, and did some test transactions. Everything seems good and pretty excited to sleep incredibly easily at night going forward.