I understand that there was a massive Bitcoin theft due to Android OS's SecureRandom function being not random enough.

I am concerned about Ian Coleman's tool having the same issue? Maybe not now, but in the future?

I plan to use Ian Coleman's HTML tool in Tails air gapped environment. Using a watch only wallet on my main PC and signing transations on an air gapped PC.

I was wondering if I should shake a dice 256 times to generate my own entropy? Would that be considered more random than Crypto.getRandomValues()?

Also I realized that the seed phrase can be more than 24 words long? 11 bits per word. So maybe use Crypto.getRandomValues() to generate 24 words, and then add another 12 words to it to get 36 words? Is this more secure or just overkill?

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By the way, how do you key in your 24 words into Trezor? Say you already have a seed phrase and buy a brand new Trezor. What do you do then? There are only 2 buttons on Trezor right?