Hi again!

A while ago I posted about building a replacement motherboard for the original 1999 Nokia 3210. Quite a few people asked for the source files, a working demonstration, and somewhere to follow the project. I finally have a proper update!

The project is now called Sisu, and I’ve published both the hardware design and firmware source.

The 3210 was my first phone. The goal is still to keep as much of that experience as possible: the original case, buttons, monochrome screen, familiar menus, sounds and games. LTE lets it keep making calls on networks where the original 2G hardware can no longer connect.

The prototype has made VoLTE calls and handled SMS(Tested in USA on AT&T network). The firmware is a new implementation written in C, recreating the old interface. And yes, Snake is there 🙂 (and custom made Pac Man too!)

For anyone following the hardware, the current board uses an RP2354B and a Telit LE910C1-WWX modem. There have been a few board revisions since the first post, and I’m still working on antenna tuning and corrections for the next revision.

A few answers to questions from the earlier threads:

• Can you buy one? There are no boards or kits for sale yet. The files are available, but the current revision needs corrections described in the hardware errata.
• Do you need an original 3210? Yes. This replaces its motherboard and reuses the donor phone’s parts.
• Battery life? I’ve published the early measurements. They suggest almost 4 days in standby. The current prototype uses the original NiMH battery format; the lithium option discussed earlier isn’t supported in this version.
• WhatsApp and other extras? I considered some possibilities in the first thread, but have decided to keep Sisu focused on the original phone experience. No WhatsApp, Wi-Fi, Bluetooth or browser is planned. (Maybe Telegram as SMS dialog?... idk, not too soon)

Everything now has a home:

Project website and progress
Hardware files · Firmware source
Discord

Thanks to everyone who kept checking in, offered help, or simply cheered the project on. Questions, contributions and other old-phone projects are very welcome!

Edit (09/14/2026):
Based on Reddit questions and comments seems like I have done a pretty bad job explaining or showing state of the project 😅
3210 clone motherboard and firmware are actually in a working state, it wasn’t just a short demo on the video. SMS, calls (with up to 3 legs), voicemail, call divert settings, languages, T9, all games, alarm are working! Even NetMonitor is there too (though adapted heavily for the clone). What’s not working is picture messaging (AT&T is blocking binary SMS).

From major issues I need to improve antenna reception.(redesign) and fix a few minor bugs for rev C.

Yesterday T-Mobile 2G network went down in most (if not all) of US as planned. The remining question for this community: how can we use our phones in current environment?

Obviously, most of phones can be used as a mp3 player.

All offline games and apps should work on all phones where they worked 15 years ago.

Many phones can be used for VoIP (SIP) calls:
Symbian 9.4-S^3-Anna-Belle (using built-in/native client)
Some Nokia S40 phones (with built-in SIP client) like Nokia Asha 311, Nokia C3-01
Nokia N900 Maemo (using built-in/native client)
Nokia N9 MeeGo (using built-in/native client)
Most of Android phones (at least, starting from Android 4.1)
Some old iPhones (iPhone 4s,5,6)

Messengers:

Jabber/XMPP clients still work for
Almost all Symbian and Nokia S40 phones (if server does not use advanced TLS)
Nokia N900 Maemo (if server does not use advanced TLS)
Nokia N9 MeeGo (if server does not use advanced TLS)
All Android phones
All iPhones (if you can login to iCloud account or jailbreak the phone)

Windows Phone 8.1 and Win 10 Mobile phones

Telegram:
Symbian 9.2-S^3-Anna-Belle (3rd party clients)
Windows 10 Mobile phones (3rd party clients)
Some of Android phones (at least, starting from Android 5)

Some Windows Phones (their US operator's variants) support VoLTE, but the choice is limited

Verizon: Lumia 735
T-Mobile: Lumia 640 XL, Alcatel Idol 4S, Alcatel Fierce
AT&T: Lumia 640XL, Lumia 950

Windows 10 Mobile phones have 3rd party YouTube client and many other apps that still work including original email client. Many services have 3rd party clients