If you sent your Ethereum transaction with a fee that is too low, you can update that fee using MyEtherWallet.
PS: The same steps also work for sending ERC20 tokens, just change the amount to the token amount in step 6
1. Open Etherscan.io
2. Search for your transaction hash
3. Click on "Click to see More" and note down the "Nonce" of your transaction
4. Open MyEtherwallet.com and connect it to the BitBox02.
5. Click "Send" und choose "Send Offline"
6. Enter the receiver address and the amount of ETH you want to send.
7. In the "Nonce" field, enter the Nonce that you have copied in step 3 of this guide and chose a transaction fee.
8. Click on "Generate Transaction", confirm the process on your BitBox02 and copy the long transaction string that's shown.
9. Scroll down on myetherwallet.com and click on "Send offline helper". Confirm to log out of your wallet.
10. Chose Section 3 "Signed Transaction" and enter the transaction string you copied in step 10 to send the updated transaction.