Stm32wle55cu LSE bypass mode seems to be enabled by default.

[Martdur]

Hello I'm facing an issues which I don't know if it's a zephyr bug or not.

I'm trying to use the RTC on Vbatt for the stm32wl series, using the RTC API.
For that I need the lse to be running with an external Xtal.

I've managed to make it work with the stm32wl55jc but I not with the Stm32wle55cu.

Reading the BCDR register with stmCubeProgrammer I've seen that the lse is on bypass mode despite the fact that I've not activated it in the device tree.
see :
.

Does someone has an idea how to disabled it ?

[Martdur]

I've managed to disabled the lse bypass mode by removing Vbatt and vdd then putting back vbatt then vdd then reprogramming.
But I can't still activate it for the rtc using thoses line doesn't do anything :
&rtc { clocks = <&rcc STM32_CLOCK_BUS_APB1 0x00000400>, <&rcc STM32_SRC_LSE RTC_SEL(2)>; status = "okay"; };
see :

[Martdur]

So I've managed to make everything working.
What've found is that I need to make a backup domain reset for this registers to be updated.
It make sense but I wonder why this reset should be done manually and can't be automatically done using the soft backup domain BDRST after a programing.
The issue that I encounter is when programming the cards in production the Vbatt is already powered so a "manual reset" can't be done.
Is someone have any input on this ?