Mosaic Chain Mainnet Onboarding Guide

Mainnet onboarding consists of a multi-step installation, registration, and connection process, each step of which is supported by detailed documentation. While none of the individual steps are particularly complex, they require attention and accuracy. Please do not attempt to complete the onboarding process intuitively or without reading the documentation! Several names, passwords, and codes must be set at various stages. These names and passwords must be carefully written down and stored in a secure place! Developers cannot view, modify, or reset them.

The Devnet test chain provided an opportunity for validator owners to test and practice the onboarding process on Devnet without the risk of financial loss, so that they could easily perform the operations during the Mainnet onboarding process. By switching to Mainnet, the number of machines on Devnet will decrease, but this test chain remains for developer testing, and those who wish can still practice on Devnet before joining Mainnet (provided they have previously minted their NFT on Devnet). Users switching from Devnet to Mainnet should chill their nodes and wait until they are not selected for block production before shutting down the node on the Devnet.

The document containing the differences and most important information regarding the switch from Devnet to Mainnet is definitely recommended for users who have tried Devnet.

With the launch of the Mainnet, or “live chain”, real assets will be issued. The fundamental feature of the blockchain is that there is no central server or central system administrator, so the executed transactions cannot be reversed or corrected afterwards. Therefore, it is important to join according to the instructions.

The Onboarding Guide consists of several chapters (separate documents) that build on each other:

1. Mainnet Onboarding Introduction + Switch from Devnet to Mainnet Information

2. Mosaic Validator OS Installer to Pendrive Guide

3. Mosaic Validator Node BIOS Setup Guide

4. Mosaic Validator Node Installation Guide

5. Mosaic Validator Onboarding Guide: Minting Validator NFT and Binding NFT to the Validator Node

6. Delegator NFT Minting Guide

7. MOS minting and Vesting

It is recommended to perform the setup processes in the specified order!

Account address

It is critical that NFTs and MOS are sent to the correct account address. NFTs sent to the wrong account address and thus lost cannot be replaced, nor can they be recovered using developer tools. Validator rights associated with NFT sent to the wrong account address will also be permanently lost, as will MOS sent to the wrong account address. In all other cases, a complete restart can be the solution if something is stuck or failed somewhere.

Seed phrase

When you create a new account in SubWallet, you are given a so-called seed phrase as the “password” for the account. These 12 English words (don’t use a translator for this!) must be kept in a safe place, because this is the only way to access the account from any device. If someone forgets or loses their account’s seed phrase, they will not be able to restore their account if necessary, and all their assets will be lost, including NFTs and MOS tokens!

If anyone else knows your account’s seed phrase, they can have full access to the account and steal all the assets on it, including NFTs and MOS tokens!

Minting

NFTs and Mosaic pretokens can be issued to the Mosaic blockchain through a so-called minting process. These are two separate steps, please perform these operations as described in the appropriate guide (5., 6. v. 7.).

A brief overview of the onboarding process (for validators) - does not replace the detailed description in the guides!

1. Create as many account addresses in SubWallet as you have validator NFTs.

2. From your Weboffice, mint your NFTs onto your SubWallet accounts.

3. Download the Validator OS to a USB drive from the provided link using the given helper tools. The download and write process takes 3–15 minutes depending on internet speed and server response time.

4. Prepare all the tools for installing the validator OS according to the documentation! Also, have a device ready with which you can take a screenshot if necessary and where you can write down all the names and passwords you entered!

5. Install the validator OS on your validator machine, as part of which your machine will also be registered on the Mosaic Blockchain VPN network. Use unique names and strong passwords! During the installation, and partly afterwards, the validator machine will automatically download the data necessary to take part in the validation.

6. The process of downloading blockchain data is called synchronization (sometimes abbreviated as sync). Since the Mainnet also needs to be synchronized with the Polkadot chain, this process can take an hour or two (sometimes more), depending on the speed of the internet. The synchronization of the chain will automatically continue from where it was interrupted during the process. However, binding the NFT to the validator machine is only possible with a synchronized chain.

7. After this, the Indexer will also synchronize during the process. This is necessary so that your validator can see the blockchain operation data on the Mosaic Explorer. The Indexer and the blockchain (Chain) are two separate components, the synchronized state of the indexer does not affect the operation of the chain. The status of the latter can be checked on the validator dashboard.

8. If you want to move the validator machine in a way that requires you to turn it off, you now have the option to do so. Turn it off professionally according to the documentation. If for some reason you do not want to or cannot validate, you must use the Chill function (pause) after binding the NFT to avoid penalties and to ensure that the blockchain remains stable.

9. When the blockchain synchronization is complete, you can bind your NFT on your account to your blockchain node and complete the onboarding process.

10. MOS reward distribution and Staking feature will be enabled later, when a sufficient number of validators have joined the Mainnet. This is definitely a quantity and not a time-dependent feature, meaning we cannot give a time estimate for when we will reach the required number of connected nodes.

Support

We can provide support only in cases where the issue is not covered in the provided documentation, or an unknown error message occurs.

For troubleshooting, we need:

• A description of the activity being performed and the exact step you were at

• The last interaction (e.g., which button was last clicked)

• A screenshot showing the error. If you're at a stage like validator OS installation (where screenshots are not possible), a readable photo taken with a phone is acceptable.

• The configuration used for onboarding (available in your bill).

We will not address any inquiries that do not include a screenshot of the issue until such an image is provided. If needed (e.g., if there's no visible error on the screenshot), please include a description of the expected behavior, the actual behavior, and why it is incorrect (e.g., didn’t load, disconnected, etc.).

20. 10. 2025.