# Unable to bind in development mode? **URL:** \ **Category:** ZYMKEY4\ **Created:** [March 9, 2019, 11:08pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449 "2019-03-09T23:08:46Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![zymbittester](https://avatars.discourse-cdn.com/v4/letter/z/3be4f8/32.png) [@zymbittester](https://community.zymbit.com/u/zymbittester)\ **Post date:** [March 9, 2019, 11:08pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/1 "2019-03-09T23:08:46Z")
I recently received my Zymkey4i and I followed the documentation for installing it on our RPi3 running Raspbian (stretch). It’s running with a 2.5A power supply. When the power is applied, the zymkey blinks rapidly (I’ll guess 5 times/sec)…then stops for 2 seconds…then blinks 5 times/sec for a second then switches to blinking 3 times/sec (for 10 blinks)…pauses for about a second…starts back up at 5 times/sec…pauses…3 times/sec (for 10 blinks)…pauses…and finally continuously blinks at 5 times/sec thereafter non-stop. Is it supposed to blink 3 times/sec all the time after it’s bound to the device? Or is this normal operation? ---
**Author:** ![Phil\_S\_Zymbit\_1](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@Phil\_S\_Zymbit\_1](https://community.zymbit.com/u/Phil_S_Zymbit_1)\ **Post date:** [March 12, 2019, 7:34pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/2 "2019-03-12T19:34:33Z")
@zymbittester The symptoms you describe indicate that your zymkey is NOT binding correctly. When bound it should blink 1 per 3 seconds. We are seeing other customers experiencing similar binding failures on 3B+ (but not 3B) and we are trying to dig in to the problem to understand the root issue. (We suspect its related to the 3B+/kernel/stretch combo that drive the I2C interface, but don’t yet know for sure). To help us in the process, please can you provide the following detail: - RPi 3B, or 3B+ ? - Stretch version ? - Anything else connected to the Pi header - in particular GPIO4, I2C ? - Is your zymkey mounted directly to the Pi Header ? - Do you have a display connected to the HDMI ? - Do you have a battery inserted in your Zymkey ? ---
**Author:** ![zymbittester](https://avatars.discourse-cdn.com/v4/letter/z/3be4f8/32.png) [@zymbittester](https://community.zymbit.com/u/zymbittester)\ **Post date:** [March 12, 2019, 7:56pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/3 "2019-03-12T19:56:32Z")
- RPi 3B, or 3B+ ? 3B+ - Stretch version ? Linux raspberrypi 4.14.98-v7+ Stretch version 9 - Anything else connected to the Pi header - in particular GPIO4, I2C ? Nothing else connected to the GPIO - Is your zymkey mounted directly to the Pi Header ? Yes, mounted directly to the GPIO - Do you have a display connected to the HDMI ? No - Do you have a battery inserted in your Zymkey ? Yes. Lithium Battery 3V, CR1025 ---
**Author:** ![Phil\_S\_Zymbit\_1](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@Phil\_S\_Zymbit\_1](https://community.zymbit.com/u/Phil_S_Zymbit_1)\ **Post date:** [March 12, 2019, 8:38pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/4 "2019-03-12T20:38:40Z")
Can you please email ([support@zymbit.com](mailto:support@zymbit.com)) us an image of the back and front of the Zymkey and let us know where you purchased it from. Thanks ---
**Author:** ![zymbittester](https://avatars.discourse-cdn.com/v4/letter/z/3be4f8/32.png) [@zymbittester](https://community.zymbit.com/u/zymbittester)\ **Post date:** [March 12, 2019, 9:30pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/5 "2019-03-12T21:30:15Z")
Email sent with photos. I purchased it directly from the Zymbit website. Let me know if you need better photos. ---
**Author:** ![zymbittester](https://avatars.discourse-cdn.com/v4/letter/z/3be4f8/32.png) [@zymbittester](https://community.zymbit.com/u/zymbittester)\ **Post date:** [March 12, 2019, 10:52pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/6 "2019-03-12T22:52:56Z")
I’ve been experimenting with creating new Raspbian Stretch images and testing different configurations, and one thing that I have found is that if you set force\_turbo=1 in the /boot/config.txt file, then binding will not happen at all. Blue light stays off (never blinks). This was with a Raspbian Stretch Lite image v4.14 from here: [https://www.raspberrypi.org/downloads/raspbian/](https://www.raspberrypi.org/downloads/raspbian/) Without the force\_turbo setting, the zymkey binds. I made this change with my original SD card and it’s binding now instead of blinking 5 times/sec, pausing, 3 times/sec, pausing, then forever 5 times/sec, etc. Or at least it’s working so far… ---
**Author:** ![zymbittester](https://avatars.discourse-cdn.com/v4/letter/z/3be4f8/32.png) [@zymbittester](https://community.zymbit.com/u/zymbittester)\ **Post date:** [March 12, 2019, 11:08pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/7 "2019-03-12T23:08:23Z")
Another part that kills the bind is setting a static ip in /etc/network/interfaces. When I attempt to set a static IP I end up losing the bind doing something like this: iface regular\_wifi inet static address 10.0.1.26 netmask 255.255.255.0 gateway 10.0.1.1 ---
**Author:** ![Phil\_S\_Zymbit\_1](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@Phil\_S\_Zymbit\_1](https://community.zymbit.com/u/Phil_S_Zymbit_1)\ **Post date:** [March 13, 2019, 6:13am UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/9 "2019-03-13T06:13:58Z")
@zymbittester thanks, this information is helpful, and consistent with what we believe is the/a root issue we are seeing on Pi3B+. We believe we have a fix in hand - currently in test. We’ll update you in 24 hours on the results. Thanks again. ---
**Author:** ![mauricebizzarri](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.zymbit.com/mauricebizzarri/32/260_2.png) [@mauricebizzarri](https://community.zymbit.com/u/mauricebizzarri)\ **Post date:** [March 13, 2019, 11:27pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/10 "2019-03-13T23:27:22Z")
I have a similar issue - 3B+ 4.14.98-v7+ 9.8 nothing else on pins battery inserted bought from your web site. In my case, it works for a while and then just stops. It requires numerous reboots to get it to work again, only to have it stop. The power supply light is steady on. ---
**Author:** ![mauricebizzarri](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.zymbit.com/mauricebizzarri/32/260_2.png) [@mauricebizzarri](https://community.zymbit.com/u/mauricebizzarri)\ **Post date:** [March 14, 2019, 12:27am UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/11 "2019-03-14T00:27:11Z")
more information. Two complete power down cycles and the Zymbit is restored. It lasts about 5 minutes before it fails again. Sometimes the light still blinks slowly, and sometimes it stops blinking. ---
**Author:** ![Phil\_S\_Zymbit\_1](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@Phil\_S\_Zymbit\_1](https://community.zymbit.com/u/Phil_S_Zymbit_1)\ **Post date:** [March 14, 2019, 4:09pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/12 "2019-03-14T16:09:14Z")
@mauricebizzarri @zymbittester - we believe have identified the root issue, which relates to how I2C is managed under Stretch. The problem is more apparent on RPi 3B+, for a variety of reasons. Our dev team has a working solution that is being run through production testing and should be available in a new release within 48 hours. Learn more \> > [Binding & Shutdown Issues - Solution in New Release](https://community.zymbit.com/t/binding-shutdown-issues-solution-in-new-release/455) Thanks to you both (and others) for notifiying and helping us identify the root issue. ---
**Author:** ![mauricebizzarri](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.zymbit.com/mauricebizzarri/32/260_2.png) [@mauricebizzarri](https://community.zymbit.com/u/mauricebizzarri)\ **Post date:** [March 14, 2019, 4:52pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/13 "2019-03-14T16:52:29Z")
Thank you for the timely reply. I have set up a modest test script that can test out any solution for an extended period of time. By the way I have your C software working with my GO test routine. I intend to release the sample GO software to the public domain as soon as I am sure it all works. If there is interest in GO in the Zymbit community I would consider the creation of a Go library that calls your C routines. Using the C to Go library is fairly straightforward in any case. ---
**Author:** ![zymbittester](https://avatars.discourse-cdn.com/v4/letter/z/3be4f8/32.png) [@zymbittester](https://community.zymbit.com/u/zymbittester)\ **Post date:** [March 17, 2019, 6:56pm UTC](https://community.zymbit.com/t/unable-to-bind-in-development-mode/449/14 "2019-03-17T18:56:23Z")
That is great news! Looking forward to the update.