This is a solution for fault tolerant seed storage. Store it in steel, paper or else, but advise not on any devices.
We wanted to store our BIP39 seed words safely. I mean safe from loss, theft and damage. Doing the first is easy, you can just store the full seed in several places. But you are subject to theft or brute force (if you split your seed to pieces). If you split the seed you can get some redundancy, but your splits are not equal (meaning you can lose some, but it’s important which one) and you make future brute force less impossible.
This tool creates equal shares (built of BIP39 words) with CRC and fault tolerance. You can set it to 2of3. When you will have three shares of which you can lose any one. 2 of 5 when you can lose and 3 of the 5,etc. There is also an optional password when you need the shares AND the password. Password is hashed 100,000 times, so brute forcing is VERY hard (advantage: easier to remember password is still good enough (not a dictionary word!)).
I believe this is much safer than most earlier options. Multisig is good, but far more complex to set it up (and screw it up).
Here is the link :
Open source, still use normal precautions. Read the readme and test with test seeds only! Use only with live seed on clean machines with no (0) network and reset the machine after, etc. (see readme).
Hope it helps some.