Quote from: nodc3 on Today at 08:28:39 AM

I created a seed phrase using electrum, it was in electrum format.

Let's assume this is now confirmed and that you don't have a spelling error in your Electrum recovery words used with BIP39 option in Electrum. Can we assume it confirmed too that you didn't alter the sequence of the Electrum recovery words?

Quote from: nodc3 on Today at 08:28:39 AM

But I wanted smth that can be restored without electrum. So I just used it as a Bip39 seed phrase, and it worked, even with a "Bip39 checksum failed".

Most other BIP39 compatible wallets likely won't^{I haven't tested it with other decent ones} allow you to proceed as Electrum does when your recovery words don't pass the BIP39 checksum test when you use Electrum recovery words as BIP39 recovery words. Likely other wallets assume the BIP39 checksum error is not desired or intended and thus don't continue from there.

Quote from: nodc3 on Today at 08:28:39 AM

Meanwhile I was reading articles about restoring a btc wallet only using a seed phrase. I found out I should use m/44'/0'/0'/0/0 for bitcoin.

Seems like those articles weren't very good or you misinterpreted it as you already said you didn't really know something about derivation paths. It also depends how a wallet expects a derivation path to be specified. There are differences unfortunately in some details.

There are also parts in Electrum that might be confusing to derivation path newbies. When you restore with the BIP39 option, as I and maybe others already wrote, Electrum expects the derivation path spec to be on the account level (m/purpose'/coin'/account'), not further.

Electrum default for legacy P2PKH address type is m/44'/0'/0' or equally m/44h/0h/0h, addresses start with 1....
Electrum default for native Segwit P2WPKH address type is m/84'/0'/0' or equally m/84h/0h/0h (bc1q... addresses).
This will also be displayed for BIP39 derivation when showing wallet details from menu Wallet>Information in Electrum.

Now when you go in Electrum to the "Addresses" tab (assuming default native Segwit addresses), right click on first green receiving address and choose "Details" from context menu, Electrum will display for "Derivation path:" of the first receiving address m/0/0, which might surprise someone who expected to see m/84h/0h/0h/0/0 here.
For Electrum the m in the address details is equal to m/84'/0'/0', both ms are not the same!
In terms of iancoleman.io/bip39 tool m in address details is the Account Extended Private or Public Key, while m in Electrum's wallet information "Derivation path:" is the BIP32 Root Key; the Master Public Key displayed at Electrum's wallet information again is the Account Extended Public Key.

I must say, I don't like this inconsistency in Electrum when the Master Key m at the wallet information display isn't the same as the m in the "Derivation path:" there. And why are address derivation paths not displayed in full path representation which definitely will confuse newbies. (Internally Electrum is consistent because for BIP39 derivation it only stores the Master Account Extended Key, not the BIP39 recovery words at all in the text JSON wallet file!)