SirrAT Overview
SirrAT is a tool included in SirrOS designed to interact with cellular modems using AT commands.
It acts as a user-friendly CLI for sending commands to a modem through a serial interface, relying internally on tools such as atinout.
SirrAT is primarily intended for diagnostics, inspection, and controlled configuration of modem parameters on Linux-based mobile devices such as the PinePhone Pro.
Typical use cases include:
- Querying modem status and network registration
- Inspecting identifiers exposed by the modem (IMEI, firmware version, etc.)
- Sending standard AT commands without manually handling serial devices
- Providing a safer abstraction than raw
echo > /dev/ttyUSB*
SirrAT does not bypass the mobile network, the operator, or legal constraints. It simply allows direct interaction with the modem firmware.
Running SirrAT
SirrAT can be launched either from the graphical menu or directly from the command line.
sirrat
If administrative privileges are required (for example, to access the modem device), SirrAT will request them through PolicyKit or sudo, depending on system configuration.
SirrAT Command Categories
SirrAT groups its functionality into logical command sets.
Device Information
These commands query read-only modem information:
- Modem manufacturer and model
- Firmware version
- Supported radio technologies
- Device identifiers exposed by the modem
Typical outputs include:
- IMEI (International Mobile Equipment Identity)
- Software revision
- Hardware revision
These commands are commonly used for diagnostics and verification after flashing firmware or debugging connectivity issues.
Network Status
Network-related commands allow you to inspect:
- Registration status (registered, roaming, searching)
- Signal strength (RSSI, RSRP, RSRQ depending on modem)
- Current radio technology (2G / 3G / LTE)
This is useful when troubleshooting:
- No service situations
- Poor signal quality
- Unexpected roaming behavior
SIM Information
SirrAT can query the SIM for information such as:
- SIM presence
- IMSI (International Mobile Subscriber Identity)
- Operator identifiers (MCC/MNC)
This information helps confirm whether the modem correctly detects the SIM and whether the subscription is active.
Advanced / Expert Commands
SirrAT provides an advanced mode intended for expert users; this mode enables IMEI changes via modem commands.
Mobile Network Basics: BTS, IMEI, and IMSI
To understand the privacy implications of modem identifiers, it is important to clarify three core concepts.
BTS (Base Transceiver Station)
A BTS is the cellular base station (antenna) your phone connects to.
The mobile network logs:
- Which BTS your device connects to
- At what time
- With which identifiers
By correlating BTS connections over time, operators (and entities with access to the data) can infer location history and movement patterns with significant accuracy.
IMEI – Device Identity
The IMEI (International Mobile Equipment Identity) is a unique identifier assigned to the hardware device.
Key properties:
- Visible to the operator every time the device registers on the network
- Independent of the SIM card used
-
Used for:
- Blacklisting stolen devices
- Detecting fraud
- Correlating usage across SIM changes
If the same IMEI appears with multiple SIMs, the network can infer that the same physical device is being reused.
IMSI – Subscriber Identity
The IMSI (International Mobile Subscriber Identity) identifies the subscriber, not the device.
Key properties:
- Stored in the SIM (or eSIM)
-
Tied to:
- Phone number
- Billing records
- Legal identity (in many countries)
- Used by the network to authenticate and track the subscriber
If the same IMSI appears on different devices, the network still sees the same person.
Why Changing Only SIM or Only Device Is Not Enough
In high-risk environments, network metadata analysis combines device identity, subscriber identity, and location.
Changing SIM Only (New IMSI, Same IMEI)
- The operator sees the same device reconnecting with a new subscriber identity.
- Past logs may already associate that IMEI with a known person.
- Correlation by location and usage patterns is trivial.
Result: the new SIM can be linked back to the original user.
Changing Device Only (New IMEI, Same IMSI)
- The operator clearly sees the same subscriber using a new device.
- From a legal and surveillance standpoint, nothing changes.
- Call patterns, contacts, and locations remain associated with the same person.
Result: the identity is preserved.
Burner Devices and Metadata Hygiene
SirrAT does not automatically anonymize your device, but it enables precise control. When combined with:
- A burner device (new IMEI)
- A burner SIM (new IMSI)
- Disciplined operational habits (controlled locations, limited contacts)
It becomes possible to minimize network correlation, effectively achieving the goals of a burner phone setup.
The advantage: unlike blindly swapping hardware or SIMs, SirrAT allows verification and monitoring, turning theory into a measurable, controllable practice.
Summary
SirrAT on SirrOS for PinePhone Pro is more than a debugging tool—it is a practical enabler for secure cellular operations:
- Provides insight into IMEI, IMSI, and BTS exposure.
- Helps confirm that device/SIM swaps are effective.
- Supports disciplined metadata hygiene in high-risk scenarios.
- Bridges the gap between theory (burner phones) and operational reality.
Privacy in mobile networks is not achieved through a single technical trick, but through informed choices, legal awareness, and operational discipline.
