Hello Christophe SCHMID ,
You need to modify ls1012ardb u-boot source code according to your custom board.
$flex-builder -c uboot -m ls1012ardb
Please go to uboot source code folder packages/firmware/u-boot, please modify include/configs/ls1012ardb.h
#define CONFIG_SYS_SDRAM_SIZE 0x40000000
=>
#define CONFIG_SYS_SDRAM_SIZE 0x10000000
Please add the following.
#undef FSL_QSPI_FLASH_SIZE
#define FSL_QSPI_FLASH_SIZE SZ_16M
Then rebuild u-boot with the following command (remove build/firmware/u-boot/ls1012ardb/output/ls1012ardb_tfa_defconfig/)
$flex-builder -c uboot -m ls1012ardb
Thanks,
Yiping