Thanks I see that I was calling my wallets cold wallets and airgapped wallets
But they are not cold at all. Maybe they are airgapped? Or maybe they are not airgapped either.

This laptop where they are stored both electrum and bitcoin core. Was once used with the internet.
It has not been turned on or connected to the internet in over a year or more. Maybe 2 years.
I checked the block explorers ( from a different machine) and the balances were still there.
I was worried it may not be sensible to ever connect that to the internet or allow it to connected with anything at all even usb.
Because nothing leaked off it yet but in future?


So I decided to make this laptop my " cold wallet" ( I understand this is not cold now) taking out my wifi card, deleting the bluetooth and disabling it and never to put the ethernet cable. Also put on airplane mode.

So i thought this machine is now airgapped nothing in and nothing out except a qr code from electrum only.
So yes I guess this isnt a cold wallet but it is now airgapped? Nothing physical touches it and no internet capacity.


That was my plan. But sadly the qr code from the watch only machine  cant contain enough info for the psbt.
This is a big problem.


So then my plan was okay, I will allow usb with the psbt into the airgapped wallet only because I have no choice. Then format it each time.
But only allow qr codes for the signed.txn out of the airgapped machine no usb out.

I though well if I only allow qr codes out from the airgapped machine then test before submitting  then what issues can happen?

Even if I did transfer a key logger into the airgapped machine then surely as long as the air gapped machine only outputs an electrum qr code ever and nothing else it should still be okay if that usb was then formatted on air gapped machine before using again


So I have my signed.txn qr code and I want to test that before broadcasting.

So I set up a 3rd laptop with electrum. Also offline, to scan in the QR code and see if the inputs out puts look okay. Just incase the watch only wallet shows me fake info or just auto broadcasts before I can detect it is about to scam me. I just want to read that qr code in human readable text before I load it to the watch only wallet. But it seems impossible to read it.
Someone said you can make it to json to read it but I dont know without using 3rd party software.

If the 3rd laptop (offline electrum just to check)  looks okay and all checks out the I know the airgap generated qr code is probably good.
I can also then test the qr code on the watch only electrum, that is running a different version of electrum downloaded at a differ time.
If that shows the correct inputs also.  Now I'm very sure this is a good signed.txn qr code. Correct?

Now I could broadcast that with the watch only wallet, but i want to broadcast on my own core full node. So more steps.

Sadly the qr code is not accepted by bitcoin core so this needs to be made to hex.

To get the hex I guess I can either use either laptop 3 or the watch only to reveal the hex of the loaded qr code. I have not tried this yet.
Or take the hex from the airgapped electrum which signed it ?

I just didnt want to touch the airgapped machine at all with usb at any point. So to get the hex off this airgapled machine without usb is an issue so i hope once I load the qr code of the signed.txn into the watch only then I can press some tab to reveal the hex that was contained in the qr code.  

If not damn.

If that does not work I can still get the airgapped machines signed.txn hex code perhaps by taking a photo of the screen in my phone and using the special select feature it turns text in images to text you can use to save to a file or just email to the machine running bitcoin core to broadcast the rawtransaction.

I could rename this thread how to get bitcoin off a machine without the internet or usb ,but I guess this would work the same for cold wallets in airgapped machine.

I suppose I got unlucky with the psbt being to large for the qr code on mine other people probably can never touch their cold or airgapped wallets physically. And can do the entire thing with QR codes.

Also most people may just be happy to broadcast their signed qr with electrum and not want to decode it to hex to send on their core node.  

So Its a bit more steps for my way to keep my old machine free from usb and internet totally.
Only communication via camera or keyboard is desirable.

I will change the title.