Somewhere under the Gotthard the blue arrow just stops moving. The cue in the lenses freezes mid-turn, because that's the last instruction your phone had before the mountain swallowed the signal. It isn't a bug in the glasses — it's physics, and it's worth understanding before you trust a heads-up display to get you through a pass or a long tunnel.
Short answer: The Even G2 has no SIM or eSIM of its own, and — as far as the published architecture shows — no independent GPS chip either. Navigate mirrors turn-by-turn cues that your paired phone's maps app already generates, sent to the lenses over Bluetooth. So navigation on the glasses is exactly as good, and exactly as fragile, as navigation on your phone at that moment. Where your phone loses its fix or its connection, the glasses lose it too.
Two different failures, often confused
"No signal" actually covers two separate problems, and they need different fixes.
The first is losing the GPS fix: your phone's chip needs a clear line of sight to satellites, and rock, concrete and steel block that completely. Inside the Gotthard road tunnel, in an underground car park, or in a narrow gorge with walls on both sides, the phone genuinely does not know where it is. Some phones fall back to estimating position from your last known speed and heading ("dead reckoning"), which is why a cue sometimes drifts oddly rather than simply vanishing.
The second is losing mobile data or WiFi: the maps app itself may need to fetch map tiles, traffic data or a recalculated route from the internet. This happens in remote valleys with weak coverage, near the border with a foreign SIM roaming oddly, or simply where no tower is in range. A phone can have a perfect GPS fix and still fail to route you, if it cannot reach the network to load the map.
Both failures look the same to you — the cue in the glasses pauses or goes stale — but only one of them is something you can prepare for in advance.
Where this actually happens in Switzerland
Switzerland is dense with exactly the terrain that breaks GPS. The Gotthard road tunnel alone runs roughly 17 kilometres with no satellite signal at all. Add the San Bernardino, Seelisberg and Vereina tunnels, plus the many smaller road tunnels tucked into nearly every alpine pass, and a single mountain crossing can mean several minutes of blind navigation. Deep, steep-sided valleys — the Lötschental, sections of the lower Engadin, the Rhône valley below high rock walls — can degrade a fix even in the open air, simply because half the sky is blocked by mountain.
None of this is specific to the Even G2 or to Even Realities. Your phone's own maps app has always had this weakness; the glasses just display whatever the phone hands them, one step removed.
What downloading offline maps actually fixes — and what it doesn't
| Problem | Downloaded offline maps |
|---|---|
| No mobile data / weak coverage in a remote valley | Fixes it — route and tiles are already on the phone |
| No GPS satellite fix inside a tunnel or deep gorge | Does not fix it — the phone still can't see the satellites |
| Rerouting after a missed turn, offline | Depends on the app — some recalculate offline, some don't |
General smartphone-navigation behaviour, not an Even-specific measurement. Test your own maps app before relying on it.
This is the part people get backwards: downloading an offline map region before a trip is genuinely useful and free, but it solves the data problem, not the satellite problem. It will not make a cue appear halfway through the Gotthard tunnel. What it will do is stop your phone — and by extension your glasses — from going blank the moment you drive into a valley with no reception at all, and it lets routing continue the instant you re-emerge into signal.
How to prepare before a mountain drive or a long hike
- Download the offline map region for your route on your phone before you set off — both Apple Maps and Google Maps let you save an area in advance.
- Glance at your next few turns before entering a long tunnel, so a frozen cue doesn't leave you guessing.
- Don't treat the HUD cue as a substitute for basic route awareness on unfamiliar alpine roads — know roughly where you're going.
- If navigation in dead zones is a core reason you're buying, test it with your own phone in a known local tunnel first; the glasses will behave exactly like your phone does.
Buy, skip, or test first?
Buy with confidence if your navigation use is everyday city and valley driving with normal coverage — that's the large majority of Swiss roads, and it works well.
Manage your expectations if you specifically need continuous guidance through long tunnels or deep alpine terrain — the cue will pause there regardless of which glasses or phone you use.
Test before you pay is the honest advice here: bring your own phone to the Zürich showroom and see how Navigate behaves, or compare how other models handle the same limitation in the AI glasses database. If you're still deciding between models, our buying guide covers what else to weigh.
Disclosure: AI-Eyewear is the authorised Swiss reseller of Even Realities. We'd rather tell you the tunnel goes dark than let you find out for the first time on the Gotthard.