STM32L4 updated HAL drivers breaks HAL_UARTEx_ReceiveToIdle_DMA

[SThom.7]

I have updated the STM32L4 HAL drivers to V1.13.6 / 14-November-2025 (1.18.2), which has broken my implementation of HAL_UARTEx_ReceiveToIdle_DMA.

Is this a fault in the new HAL drivers or does user code need to be updated inside the HAL_UARTEx_RxEventCallback?

[TDK]

Code within HAL_UARTEx_ReceiveToIdle_DMA hasn't changed for several years. Probably not the problem.

https://github.com/STMicroelectronics/stm32l4xx-hal-driver/blame/047a8610c7dc0dcfdb4cd63b86cd3a2cbd3e5899/Src/stm32l4xx_hal_uart_ex.c#L945

Debug your code. Hit pause, understand what is breaking and then try to fix that. Don't look for a magic solution.

Do a diff on your code before/after the update to understand the differences. CMSIS and header files need to be in sync with HAL files.

[SThom.7]

Diff shows the code around this feature has definitely been updated in hal_uart.c

Release notes:

• Provide accurate position in RxEventCallback when ReceptionToIdle mode is used with DMA, when UART and DMA interrupts process is delayed."

[SThom.7]

I have found the fault in stm32l4xx_hal_uart.c

Inside the function UART_DMAReceiveCplt, inside the check for HAL_UART_RECEPTION_TOIDLE line 3902, this line of code is missing.

huart->RxXferCount = 0;