The device comes pre-flashed with EZSP 6.9.1_2 but there are unresolved issues with Tasmota and we currently only support 6.7.x. You need to downgrade the flash firmware to 6.7.9. Simply use the **Firmware Upggrade** feature of Tasmota, it will automatically detect that the firmware is for the EFR32 and not for Tasmota.
## EFR32, EmberZNet and EZSP Protocol Versions
EZSP stands for "EmberZNet Serial Protocol" which is the default serial interface used in compatible Zigbee coordinator firmware for the Silicon Labs EFR32 hardware family such as the EFR32MG21/MGM210 and EFR32MG12/MGM12 series.
Silicon Labs do not currently have a consolidated list of changes by EmberZNet SDK or EZSP protocol versions. The EZSP additions, changes and deletions have only ever been listed in the [Zigbee EmberZNet Release Notes](https://www.silabs.com/search#q=Zigbee%20EmberZNet%20Release%20Notes&t=All&sort=relevancy) (EmberZNet SDK) under the "New items" section as well as the matching UG100 EZSP Reference Guide included with each EmberZNet SDK release.
The largest change was between EZSP v4 (first added in EmberZNet 4.7.2 SDK) and EZSP v5 that was added in EmberZNet 5.9.0 SDK which requires the Legacy Frame ID 0xFF. The change from EZSP v5 to EZSP v6 was done in EmberZNet 6.0.0 SDK. The change from EZSP v6 to EZSP v7 was in EmberZNet 6.4.0 SDK. EmberZNet 6.7.0 SDK added EZSP v8 (and Secure EZSP Protocol Version 2).
Perhaps more important to know is that EZSP v5, v6 and v7 (EmberZNet 6.6.x.x) use the same framing format, but EmberZNet 6.7.x.x/EZSP v8 introduced new framing format and expanded command id field from 8 bits to 16 bits.
See Silabs [Zigbee & Thread Knowledge Base Articles List](https://silabs-prod.adobecqms.net/community/wireless/zigbee-and-thread/knowledge-base.entry.html/2020/04/01/zigbee_thread_knowledgebasearticleslist-ih5r) for background information.