Resolved! Call HAL_ETH_ReleaseTxPacket() from ISR context?
I am connecting a TCP/IP stack to the HAL_ETH driver of an STM32F7xx. I am using https://github.com/STMicroelectronics/STM32CubeF7/blob/master/Projects/STM32F767ZI-Nucleo/Applications/LwIP/LwIP_HTTP_Server_Netconn_RTOS/Src/ethernetif.c as a starting ...