# Re-register an already registered TTIG **URL:** \ **Category:** TTIG - The Things Indoor Gateway\ **Created:** [November 11, 2024, 12:49am UTC](https://www.thethingsnetwork.org/forum/t/re-register-an-already-registered-ttig/69730 "2024-11-11T00:49:06Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![mteaguu](https://www.thethingsnetwork.org/forum/letter_avatar_proxy/v4/letter/m/f04885/32.png) [@mteaguu](https://www.thethingsnetwork.org/forum/u/mteaguu)\ **Post date:** [November 11, 2024, 12:49am UTC](https://www.thethingsnetwork.org/forum/t/re-register-an-already-registered-ttig/69730/1 "2024-11-11T00:49:06Z")
I am having an issue that is similar to this discussion. I’m tyring to use “The Things Indoor Gateway”, when I try to register the device I get the error “gateway with EUI already exists”. The device is from my university, and someone has already used this device for a previous project. On the setup page:[[The Things Indoor Gateway | The Things Stack for LoRaWAN](https://www.thethingsindustries.com/docs/gateways/models/thethingsindoorgateway/)], it says that the device must be authorized to be re-registered using the gateway-id, within the CLI. But I do not know the gateway ID, and I think I need to be logged into the original users account to use the command. My question is, is there anyway I can still use “The Things Indoor Gateway”, without getting access to the previous users account? ---
**Author:** ![descartes](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/descartes/32/47220_2.png) [@descartes](https://www.thethingsnetwork.org/forum/u/descartes)\ **Post date:** [November 11, 2024, 9:59am UTC](https://www.thethingsnetwork.org/forum/t/re-register-an-already-registered-ttig/69730/2 "2024-11-11T09:59:39Z")
> [@mteaguu](#): > > I am having an issue that is similar to this discussion. Only barely similar! Devices are not gateways - so moving this to a new topic ---
**Author:** ![descartes](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/descartes/32/47220_2.png) [@descartes](https://www.thethingsnetwork.org/forum/u/descartes)\ **Post date:** [November 11, 2024, 10:03am UTC](https://www.thethingsnetwork.org/forum/t/re-register-an-already-registered-ttig/69730/3 "2024-11-11T10:03:22Z")
> [@mteaguu](#): > > when I try to register the device I get the error “gateway with EUI already exists”. You don’t register a TTIG, the docs talk about claiming - are you checking the docs? In the first instance you need to try to reach the previous user to ask them to issue a claim code. Or you can ask very nicely in Slack for a member of staff to do this for you for free. Or just plug it in and use it - you won’t be able to see the console but it should still do the gateway thing. ---
**Author:** ![lessat](https://www.thethingsnetwork.org/forum/letter_avatar_proxy/v4/letter/l/d9b06d/32.png) [@lessat](https://www.thethingsnetwork.org/forum/u/lessat)\ **Post date:** [November 20, 2024, 1:36pm UTC](https://www.thethingsnetwork.org/forum/t/re-register-an-already-registered-ttig/69730/4 "2024-11-20T13:36:29Z")
A possible way would be to generate your own EUI. You could do this based on your MAC address. Here is a general overview of how it works: 1. Split the MAC address into two halves: A MAC address consists of 48 bits and is divided into two halves. 2. Insert FFFE: Insert the hexadecimal values FFFE in the middle of the address to expand it to 64 bits. 3. Change the Universal/Local bit: Change the seventh bit (Universal/Local bit) of the MAC address to convert the address from local to global or vice versa. Here is an example: MAC address: `00-14-22-01-23-45` Split and insert FFFE: `00-14-22-FF-FE-01-23-45` Change the Universal/Local bit: Change the seventh bit of the first octet. In this case, `00` changes to `02`. Result: `02-14-22-FF-FE-01-23-45` ---
**Author:** ![descartes](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/descartes/32/47220_2.png) [@descartes](https://www.thethingsnetwork.org/forum/u/descartes)\ **Post date:** [November 20, 2024, 3:56pm UTC](https://www.thethingsnetwork.org/forum/t/re-register-an-already-registered-ttig/69730/5 "2024-11-20T15:56:10Z")
There is absolutely no need to generate an EUI for the TTIG - it comes with one and you can’t change it. And there is a generator for EUI’s revealed by forum search to be found at [Random EUI or Key generator | descartes](https://descartes.co.uk/CreateEUIKey.html)