# Electrum 2/3 PSBT Multi-sig
Keystone firmware version V1.1.1 (BTC-Only) or newer supports PSBT Muti-signature function. This instruction will show how to create a 2/3 PSBT Multi-signature with 2\*Keystone, 1\*Coldcard and Electrum V4.1.2 in details.
## **I. Preparation**
1\. [Firmware](https://keyst.one/firmware?locale=en) version V1.1.1 (BTC-Only) or newer running on Keystone Essential or Pro.
(Please read[ How to upgrade firmware](https://support.keyst.one/getting-started/firmware-upgrading) for more details.)
2\. Coldcard upgraded to firmware version V2.1.0 or newer.
3\. MicroSD card (≤512GB; Default FAT32 format).
{% content-ref url="../../../getting-started/firmware-upgrading/how-to-format-a-microsd-card-to-fat32" %}
[how-to-format-a-microsd-card-to-fat32](https://support.keyst.one/getting-started/firmware-upgrading/how-to-format-a-microsd-card-to-fat32)
{% endcontent-ref %}
4\. Electrum Wallet (V4.1.2 or newer) running on PC/Mac.
{% hint style="info" %}
**Tips**: If you want to switch to \[Test Net], please go to "Keystone > Settings > Blockchain > Test Net" and "Coldcard > Settings > Blockchain > Test Net". Then continue with the following steps.
{% endhint %}
## **II. Create a 2/3 multisig wallet with 2\*Keystone and 1\*Coldcard**
### - Create multisig wallet on Coldcard
1\. Export Keystone’s Xpub to microSD card
1\) Insert the microSD card into Keystone.
2\) Touch \[Menu] > \[Multisig Wallet] > Press the \[•••] button on the top right > \[Show/Export XPUB].
3\) Touch \[Export All] > \[Export].
{% hint style="info" %}
**Tips:**
① Please repeat this step on 2\*Keystone.
② If you were using 1\*Keystone and 2\*Coldcard to create a 2/3 PSBT Muti-signature wallet, please export Xpubs from 1 Keystone and 2 Coldcard (\[Settings] > \[Multisig Wallets] > \[Export XPUB]).
{% endhint %}
2\. Create multisig wallet on Coldcard
1\) Take out the microSD card from Keystone and insert it into Coldcard.
2\) \[Settings] > \[Multisig Wallets] > \[Create Airgapped].
3\) Set address type (Default-P2WSH) and the number of cosigner (2 of 3).
4\) Confirm (√) and complete creating a 2/3 multisig wallet.
3\. After the previous steps, you will get 2 files on your microSD card
1\) “export-CC-2-of-3.txt” - this is for importing multi-sig wallet to Keystone - allows Keystone to check the genuinity of multisig when signing.
2\) “el-CC-2-of-3.json” - this is for creating watch-only wallet on Electrum.
**Tips:** If you didn’t get these two files, please export manually by following instructions:
1\) Export the multisig wallet file (for importing multisig wallet to Keystone) to the microSD card
① Insert the microSD card into Coldcard.
② \[Settings] > \[Multisig Wallets] > \[2/3: CC-2-of-3] > \[Coldcard Export] > Export the “export-CC-2-of-3.txt” file to the microSD card.
2\) Export the multisig wallet file (for creating watch-only wallet on Electrum) to the microSD card
① Insert the microSD card into Coldcard.
② \[Settings] > \[Multisig Wallets] > \[2/3: CC-2-of-3 > \[Electrum Export] > Export the “el-CC-2-of-3.json” file to the microSD card.
### - Import multisig wallet file to Keystone
1\. Take out the microSD card from Coldcard and insert it into Keystone.
2\. Touch \[Menu] > \[Multisig Wallets] > \[Import Multisig Wallet].
3\. Select file “export-CC-2-of-3.txt” > Touch \[Confirm].
### - Import multisig wallet file to Electrum and create watch-only wallet
1\. Take out the microSD card from Keystone and insert the it into PC/Mac.
2\. Run Electrum and click on \[Choose...] > Select file “el-CC-2-of-3.json” > \[Open] > \[Next] > \[No].
{% hint style="info" %}
**Note:** As Electrum doesn’t have a Keystone plugin (we are working on that), Keystone can’t generate a Electrum skeleton json file. So you have to export the Electrum skeleton json file from Coldcard to set up the watch-only wallet on Electrum.
{% endhint %}
## **III. Sending bitcoin from the 2/3 multisig address (2\***Keystone **& 1\*Coldcard)**
### - Generate multisig transaction on watch-only wallet(Electrum) and export unsigned multisig transaction file to MicroSD card.
1\. Click \[Send] > Enter destination address and amount > \[Pay] > \[Send].
2\. Click \[Export] > \[For hardware device; include Xpubs] > \[Export for file] > \[Save].
### - Partially sign multisig transaction on Coldcard
1\. Take out the microSD card from PC/Mac and insert it into Coldcard.
2\. \[Ready To Sign] > Confirm and export partially signed multisig transaction file to microSD card.
### - Complete sign multisig transation on Keystone
1\. Take out the microSD card from Coldcard and insert it into Keystone.
2\. Enter Multisig Wallet > Press "microSD card" icon on the top right > Select the partially signed transaction file > Confirm transaction details and press \[Sign].
3\. Password Verification > Press \[Export] to export a fully signed multisig transaction file to the microSD card.
### - Broadcast multisig transaction with Electrum
1\. Click \[Tools] > \[Load transaction] > \[From file] > Select fully signed multisig transaction file > \[Open] > \[Broadcast].
Instructions recommended: [Delete Multisig Wallet on Keystone](https://support.keyst.one/advanced-features/more/delete-multisig-wallet)
.jpg?alt=media&token=68811e7b-4366-437a-b21c-acb9b46c3d86)
