I use Spirit1 both with 433Mhz and 868Mhz on the same custom-designed board with stm32l1. The radio parameters are set according to the individual transceiver and the software configuration is done seperately as well. CSMA is enabled for both of them. There is no problem running the device with single transceiver (433 or 868 Mhz only). It sends/receives basic packtes properly (half duplex). CSMA works fine. But when I merged two different codes into one project and started to send/receive packets like previosuly, I meet Brown out event after every Backoff counter is reached flag. It continuously stays in Brownout once after Backoff is reached. For now the merged code runs only the selected transceiver (by software) in the device. It seems to work good except the Brownout issue due to CSMA I think. Because I don’t met Brownout if I don’t use CSMA. Do you have any idea what can cause that problem? And can you give some extra explanation about Brownout event.