Cannot flash SPI-NOR MX25U6435F on Odroid N2+

[Christian Kohlschütter]

Hi all,

I'm trying to flash the MX25U6435F 8MB SPI-ROM integrated in ODROID N2+ boards.

Using Linux 6.14 (or any other recent mainline kernel), I can't seem to get any changes persisted:

sudo flashcp -v u-boot.spi.bin /dev/mtd0
Erasing blocks: 289/289 (100%)
Writing data: 1155k/1155k (100%)
Verifying data: 10k/1155k (0%)File does not seem to match flash data. First mismatch at 0x00000000-0x00002800

Relevant kernel configs:
CONFIG_MTD_SPI_NOR=m
CONFIG_MTD_SPI_NOR_SWP_DISABLE=y  # does not make a difference

With the same userland tools (mtd-utils 2.2.1-r0 running on Alpine Linux), flashing succeeds when using their custom kernel (based upon 4.9.337; odroidg12-4.9.y branch from https://github.com/hardkernel/linux)

Note that both kernels need a custom DTB to enable SPI (see ic/meson-g12b-odroid-n2.dtsi).

Linux 6.14 needs these additional entries to meson-g12b-odroid-n2-plus.dts (odroid's 4.9.337 needs similar changes)

&spifc {
        status = "okay";
        pinctrl-0 = <&nor_pins>;                                           
        pinctrl-names = "default";                                         
                                                            
        mx25u64: flash at 0 {                                  
                #address-cells = <1>;
                #size-cells = <1>;             
                compatible = "mxicy,mx25u6435f", "jedec,spi-nor";
                reg = <0>;                                       
                spi-max-frequency = <104000000>;                 
        };
};

&sd_emmc_c {
        pinctrl-0 = <&emmc_ctrl_pins>, <&emmc_data_4b_pins>, <&emmc_ds_pins>;
        bus-width = <4>;
};

Any help pointing me in the right direction is greatly appreciated.

Thanks,
Christian