External flash getting corrupted after MCU reboot

RE: External flash getting corrupted after MCU reboot

Menon — Thu, 19 Mar 2026 10:11:01 GMT

Hello,

Glad to hear that the your issue has been resolved.

Kind Regards,

Abhijith

RE: External flash getting corrupted after MCU reboot

Golaz — Wed, 18 Mar 2026 20:13:20 GMT

The issue was I set sck frequency of external flash to 133 MHz, while nRF52840 QSPI peripheral goes only up to 32 MHz.
No build warning or error was issued.
I have no idea what the clock frequency was set to QSPI peripheral.

Setting sck frequency of external flash to 20 MHz. It works now.

RE: External flash getting corrupted after MCU reboot

Golaz — Wed, 18 Mar 2026 18:27:38 GMT

I have noticed that immediately after MCU reset flash CS pin is pulled low 3 times with approx. 1us pulse length. And CLK is also toggled a few times. This happens BEFORE mcuboot main() function is entered, so it must be done in the kernel.