Lessons from the Field: Enabling BIP/STK for SGP.32 and eSIM IoT Deployments

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As SGP.32 and the IoT Profile Assistant (IPA) gain traction in the eSIM world, more deployments are relying on eUICCs (embedded SIM cards) that can autonomously initiate remote SIM provisioning. For that to work, many eUICCs require the ability to open a TCP/IP channel via the device’s modem, known as Bearer Independent Protocol (BIP).

While nearly all modern IoT modems released in the past five years support this functionality, we continue to see real-world challenges where the modem doesn’t have BIP or STK (SIM Toolkit) properly enabled by default — which can block eSIM provisioning entirely.

If you’re new to eSIM for IoT, check out our Simplex eSIM overview page to learn how our architecture is built around SGP.32, multi-carrier support, and global scalability.

A Real-World Example: ChatGPT Helped — Until It Didn’t

At Simplex Wireless, we often leverage tools like ChatGPT to speed up device configuration and troubleshooting. In fact, we even wrote about it earlier this year in our guide: **How to Enable BIP/STK on Modems for eSIM IoT SGP.32 Deployments**

But recently, we hit a frustrating roadblock while trying to get BIP/STK working on a Quectel EC25G modem embedded in a cellular router.

ChatGPT initially recommended the following command to enable STK:

AT+QSTK=1

The logic appeared sound. On some Quectel modules, this command is used to manually activate proactive commands — such as triggering a tone, menu item, or network command — via the SIM Toolkit. However, what ChatGPT missed was that SGP.32’s IoT Profile Assistant expects the modem to automatically respond to eUICC commands without any manual trigger from the host.

This misunderstanding caused a delay of several weeks as we debugged the issue.

The Correct Configuration for Quectel EC25G (and Similar)

What was actually needed to enable automatic BIP functionality was a different set of commands entirely:

AT+QSTK=0

AT+QCFG="bip/auth",0

Here’s what these commands do:

• AT+QSTK=0: This disables manual STK triggering, allowing the SIM card to operate in automatic mode.
• AT+QCFG="bip/auth",0: This disables BIP authentication, enabling the SIM to initiate the TCP/IP channel automatically via the modem.

This configuration effectively allows the IPAe (IoT Profile Assistant embedded) on the eUICC to open the BIP channel, complete remote profile operations, and interact with the EIM (eSIM IoT Manager) without needing host-side intervention.

To learn more about how our in-house EIM platform supports SGP.32-based eSIM management, visit our product overview page.

Why This Matters for SGP.32 IoT Deployments…

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This article was created by Jan Lattunen, CCO Simplex Wireless

Jan Lattunen manages Sales and Marketing for Simplex Wireless. Jan has 20+ years’ experience in working with SIM card technology and was involved in launching the eSIM in North America with major carriers and OEMs. His expertise in telecommunications is around SIM cards. You can connect with Jan on https://linkedin.com/in/JanLattunen or send us an email as sales@simplexwireless.com for more information.