But they are not cold at all. Maybe they are airgapped? Or maybe they are not airgapped either.
It's one and the same. A wallet isn't airgapped/cold if it periodically connects to the internet or has done so in the past.
This laptop where they are stored both electrum and bitcoin core. Was once used with the internet.
That's what I thought. In that case, it's not an airgapped setup. A properly airgapped computer requires that you reformat the drive and install a clean OS on it. Linux is recommended. The computer shouldn't possess network connectivity hardware, so that you or someone else can't even mistakenly connect it to the internet.
I checked the block explorers ( from a different machine) and the balances were still there.
A hot wallet doesn't necessarily mean an unsafe wallet, and you can use them just fine. But the chances that something goes wrong is significantly higher on a computer with a hot wallet and especially one that you use for everyday tasks and internet browsing.
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.
The proper way is to make it airgapped from the beginning. A hot wallet can't be considered cold if the keys were part of an internet-connected machine.
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.
You can't wipe away the past like that. Yes, your computer can't connect to the internet any longer. But that wasn't true in the past. You could have infected it with some malware in the past that is now lying there and waiting.
Here is another analogy for you. If you have had sex, you are no longer a virgin. You can't consider yourself virgin from next month if you intend to stop having sex. You had intercourse in the past.
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.
I don't know why that is. Sorry, can't help you there.
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.
That will work. You can save the PSBT on a USB or MicroSD card to transfer data to and from the two computers.
I though well if I only allow qr codes out from the airgapped machine then test before submitting then what issues can happen?
If the transaction was created properly and signed, I don't know what can go wrong during the broadcast stage. I think you are thinking too much about it.
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.
I don't know why you would go through this trouble of setting up a third device and testing the transactions like you are planning. What do you expect will happen if you don't carry out those tests?
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?
You have lost me. I have never heard of anyone including a third device in an airgapped setup for the purposes you mentioned.