Zyxel NR7101🔗

TLDR; Don't buy it, its poop

Info🔗

An outdoor 5G router that was primarily offered by Elisa initially, but now it’s hard to find through ISPs; you'll have to buy it yourself if you want one.
On paper (from 2020 until recently), it was the best device in its price range.
Arguably the biggest downside is the 1Gbps Ethernet port, as I can actually hit 1000Mbps when the network load (for the ISP tower) is low and the weather is good.
Additionally, the "Zyxel Air" mobile app is terrible - it doesn't work for most people, and it didn't work for me either.

While newer devices have better hardware, this Zyxel has a solid signal boost at 10dBi compared to others that offer less. Even if a device has better internals, it won't change the maximum speed of the ISP tower.

A modern alternative would be the MikroTik ATL 5G R16, which features 16dBi—a massive jump in signal strength. However, that device is IP-66 rated, whereas the Zyxel's IP-68 rating gives more peace of mind. For my setup, 16dBi isn't necessary anyway since 10dBi already provides a maximum signal strength. If even better reception were needed, one would have to buy a separate 5G router with dedicated external antennas to reach 20dBi, but that has its own issues.

Configuration🔗

When the Zyxel NR7101 is used with an Elisa SIM card, the device configures itself automatically, pulling the necessary settings from the ISP. IP Passthrough mode is activated automatically.

I have also configured a hidden Wi-Fi network so that if I lose access via the Ethernet cable for any reason, I can still access the device directly with my phone.

Known Issues and Solutions🔗

Unfortunately, the modem firmware that comes from the factory is terrible. The list of issues looks something like this. Version A03 (R11A03) is the oldest modem firmware version that comes with Elisa-branded devices (technically R01A04 is the oldest, but Elisa or Zyxel updated them to A03).

"Torrent Hanging" (NAT Table Memory Leak)🔗

In A03, the modem chip has a very small memory allocation for tracking connections ('states')

Torrents create thousands of UDP/TCP states. The firmware doesn't clear old states fast enough, the RAM fills up, and the modem's internal processor (Quectel module) crashes while the Zyxel web interface remains active.

Fix: Improved Garbage Collection in the R13 branch

Inactive sessions are now cleaned up aggressively, preventing the memory saturation that previously required a reboot.

"Zombie Connection" (PDP Context Freeze)🔗

You see 4–5 signal bars and 'Connected' status, but nothing loads

This is a PDP context freeze. The modem loses its logical handshake with the provider but fails to notify the Zyxel OS that the connection has dropped.

Fix: Newer firmware handles 'keep-alive' requests much better

If the data path hangs, the modem can now silently reset the data session (context) in milliseconds without dropping the entire 5G link.

IP Passthrough MAC Address Loss🔗

When using IP Passthrough, the NR7101 should pass the public IP to your internal router

In A03, the modem often "forgets" the internal router's MAC address under heavy load, causing the internal router to think the WAN connection is down.

Fix: R13A04 includes a rewritten ARP (Address Resolution Protocol)

A new ARP handler for bridge mode makes the "handshake" between the Zyxel and your internal router much more stable.

5G NSA (Non-Standalone) Stability🔗

The device currently uses NR-NSA mode

This requires a "primary" LTE band (Band 1) and a "supplementary" 5G band (N78). In early firmware, even a millisecond fluctuation in the LTE signal would cause the 5G connection to drop, taking 30–60 seconds to renegotiate.

Fix: Improved 'Inter-RAT' (Radio Access Technology) handovers

The newer firmware is much "stickier" - it holds onto the 5G band much more aggressively even when the LTE anchor signal fluctuates.

Thermal Throttling and Power Management🔗

The Snapdragon X55 chip inside the Zyxel runs hot

A03 had poor thermal management. When it overheated (usually during large downloads), the chip would simply drop secondary frequency bands (e.g., Band 3), causing a sharp drop in speed.

Fix: More precise power states

The modem now scales power consumption better, allowing it to stay in a "high-speed" state longer before it needs to throttle due to heat.

CA (Carrier Aggregation) Combination Logic🔗

My Band 3 is at -110 dBm (very weak)

In A03, the modem often tries to pull data from a weak band just because it's "available," which actually slows down the total speed (known as "timing inefficiency").

Fix: Significantly smarter logic in the R13 branch

If a band is too weak or noisy (like my Band 3), the modem ignores it and concentrates resources on clean bands (Band 1 and N78), resulting in higher and more stable speeds.

Bufferbloat (Ping Spikes)🔗

Under heavy load, A03's 'buffers' (data queues) become too large

This causes ping to spike from 20ms to 500ms the moment you start a download.

Fix: Better 'Active Queue Management' implementation

This keeps data moving through the modem faster and reduces the "lag" you feel when someone else in the house starts streaming video.

Summary: Is all this hassle worth it?🔗

After updating, yes. The signal is actually very good (SINR 23), but the device's "brain" (A03 firmware) just couldn't handle the traffic. By updating to R13A04, you aren't just fixing bugs—you are essentially getting a new router. It starts behaving much more like a "set and forget" fiber connection rather than a "reboot once a day" 5G connection.

Updating🔗

The device firmware must be at least (ABUV.10) or the latest version provided by Zyxel.
EDIT: Zyxel no longer gives firmware links...

The current Module Firmware is RG502QEAAAR11A03M4G, which is that terrible factory firmware.
EDIT: Updated to R13A04 and now i have new problems...
This thing just sucks ass, don't buy it.

Update Sequence🔗

RG502QEAAAR11A03 to R11A06 (This gets you off the buggy A03 version).
RG502QEAAAR11A06M4G to R11A07 (Stability fix).
RG502QEA_R11A07 to ZYXELR13A02 (Most important: This moves the modem to the new "Zyxel-optimized" branch).
ZYXELR13A02 to ZYXELR13A04 (Final stability and speed update).

~~Zyxel NR device and modem firmware can be downloaded from this~~ ~~forum page~~.
If you want the latest device firmware, ABUV.11 is available on Zyxel's Download Library page.