# GENERAL **URL:** https://community.zymbit.com/c/faq/25.md [Latest](https://community.zymbit.com/latest.md) · [Categories](https://community.zymbit.com/categories.md) · [Tags](https://community.zymbit.com/tags.md) --- ## [Invalid GPG key for apt repo](https://community.zymbit.com/t/invalid-gpg-key-for-apt-repo/1697)
**Author:** [@ptaag](https://community.zymbit.com/u/ptaag)\ **Replies:** 3\ **Last updated:** [October 1, 2024, 7:36am UTC](https://community.zymbit.com/t/invalid-gpg-key-for-apt-repo/1697 "2024-10-01T07:36:35Z")
Hello Zymbit team, Looks like GPG key for apt repo is expired or invalid. I have got an error during run of install\_zk\_sw.sh scirpt: W: GPG error: zk-sw-repo.s3\*\*\*\*\*\*/apt-repo-bookworm-aarch64 bookworm InRelease: The… --- ## [Zero Trust Network Access (ZTNA) Options](https://community.zymbit.com/t/zero-trust-network-access-ztna-options/1676)
**Author:** [@GMWCTO](https://community.zymbit.com/u/GMWCTO)\ **Replies:** 1\ **Last updated:** [July 22, 2024, 2:05pm UTC](https://community.zymbit.com/t/zero-trust-network-access-ztna-options/1676 "2024-07-22T14:05:30Z")
I’m exploring Zero Trust (ZT) technologies, and found some sound descriptions on the CloudFlare website: What is Zero Trust?. Has Zymbit or AWS (for that matter) provided any insights in how to apply ZT / ZTNA technolog… --- ## [Raspian bookworm](https://community.zymbit.com/t/raspian-bookworm/1603)
**Author:** [@tennisparty](https://community.zymbit.com/u/tennisparty)\ **Replies:** 10\ **Last updated:** [January 15, 2024, 10:28pm UTC](https://community.zymbit.com/t/raspian-bookworm/1603 "2024-01-15T22:28:39Z")
Hello, Is it possible to send a message on a dedicated thread when support for raspian bookworm is released? Many thanks, Sam --- ## [Zkbootrtc.service](https://community.zymbit.com/t/zkbootrtc-service/1613)
**Author:** [@tennisparty](https://community.zymbit.com/u/tennisparty)\ **Replies:** 0\ **Last updated:** [December 16, 2023, 4:07pm UTC](https://community.zymbit.com/t/zkbootrtc-service/1613 "2023-12-16T16:07:55Z")
Is it OK to disable zkbootrtc.service I am using another device (wittypi) for timekeeping with an RTC. --- ## [Encryption with Air Gap](https://community.zymbit.com/t/encryption-with-air-gap/1560)
**Author:** [@Bob\_of\_Zymbit](https://community.zymbit.com/u/Bob_of_Zymbit)\ **Replies:** 0\ **Last updated:** [August 21, 2023, 11:27pm UTC](https://community.zymbit.com/t/encryption-with-air-gap/1560 "2023-08-21T23:27:53Z")
This is a post containing the steps for encrypting your root file system offline using the Zymkey, HSM4, HSM6, or SCM on the bullseye 32 bit desktop image. Append “arm\_64bit=0” to /boot/config.txt (necessary for 32bit … --- ## [Using an Alternative I2C Address](https://community.zymbit.com/t/using-an-alternative-i2c-address/1044)
**Author:** [@Michelle\_of\_Zymbit](https://community.zymbit.com/u/Michelle_of_Zymbit)\ **Replies:** 0\ **Last updated:** [December 12, 2020, 12:55am UTC](https://community.zymbit.com/t/using-an-alternative-i2c-address/1044 "2020-12-12T00:55:24Z")
Applicable Products The information included in this post applies to Zymkey 4i and HSM4. You can change the I2C address through our standard APIs: C: zkSetI2CAddr Python: set\_i2c\_address The I2C communication be… --- ## [Should I use an External Battery on my Zymkey / HSM?](https://community.zymbit.com/t/should-i-use-an-external-battery-on-my-zymkey-hsm/1041)
**Author:** [@Michelle\_of\_Zymbit](https://community.zymbit.com/u/Michelle_of_Zymbit)\ **Replies:** 2\ **Last updated:** [July 8, 2021, 3:26pm UTC](https://community.zymbit.com/t/should-i-use-an-external-battery-on-my-zymkey-hsm/1041 "2021-07-08T15:26:20Z")
The following table compares Zymkey and HSM operational modes while connected to Main Power, Battery Power, and No Power. The battery is required to maintain the Real Time Clock and the perimeter detect circuits when th… --- ## [How to integrate Zymbit with AWS Credentials Provider](https://community.zymbit.com/t/how-to-integrate-zymbit-with-aws-credentials-provider/1144)
**Author:** [@Connor\_of\_Zymbit](https://community.zymbit.com/u/Connor_of_Zymbit)\ **Replies:** 1\ **Last updated:** [April 6, 2021, 9:59pm UTC](https://community.zymbit.com/t/how-to-integrate-zymbit-with-aws-credentials-provider/1144 "2021-04-06T21:59:03Z")
Introduction The AWS Credentials provider can give a remote device AWS credentials if it has a valid certificate. The device certificate is stored inside AWS IoT’s service and can be revoked, deactivated or deleted at a… --- ## [Real Time Clock](https://community.zymbit.com/t/real-time-clock/1014)
**Author:** [@Michelle\_of\_Zymbit](https://community.zymbit.com/u/Michelle_of_Zymbit)\ **Replies:** 0\ **Last updated:** [November 16, 2020, 8:10pm UTC](https://community.zymbit.com/t/real-time-clock/1014 "2020-11-16T20:10:02Z")
Applicable Products The information included in this post applies to Zymkey 4i, HSM4, and HSM6. Standard Zymkey and HSMs are supplied with a Real Time Clock (RTC). This capability can be useful for platforms which do n… --- ## [About Zymbit](https://community.zymbit.com/t/about-zymbit/925)
**Author:** [@Michelle\_of\_Zymbit](https://community.zymbit.com/u/Michelle_of_Zymbit)\ **Replies:** 0\ **Last updated:** [August 18, 2020, 1:33am UTC](https://community.zymbit.com/t/about-zymbit/925 "2020-08-18T01:33:45Z")
PRODUCTS How do all of these products fit together? The core of all Zymbit products is integrated security in the form of hardware security modules. Zymbit currently has three types: Zymkey 4, HSM4, and HSM6. These modu… --- ## [Power Quality - How it Impacts Software & System Reliability](https://community.zymbit.com/t/power-quality-how-it-impacts-software-system-reliability/243)
**Author:** [@Phil\_S\_Zymbit\_1](https://community.zymbit.com/u/Phil_S_Zymbit_1)\ **Replies:** 5\ **Last updated:** [April 8, 2020, 6:27am UTC](https://community.zymbit.com/t/power-quality-how-it-impacts-software-system-reliability/243 "2020-04-08T06:27:30Z")
Applicable Products The information included in this post applies to all Zymbit security modules. Power & Security Poor power quality can result in unstable and potentially insecure operation of your single board comput…