I'm working on an imx6ul based off the NXP imx6ul-evk. One difference is the qspi nor is a different device (JEDEC 20bb19 instead of 20ba19). When the qspi is included and initialized, the watch dog fails to reboot the board during a "shutdown -r now". Same kernel (slightly different dtb) works find on the imx6ul-evk.
I see some comments regarding watchdog and qspi for the imx6sx.
* Some i.MX6 boards use WDOG2 to reset external pmic in bypass mode,
* so do WDOG2 reset here. Do not set SRS, since we will
* trigger external POR later. Use WDOG1 to reset in ldo-enable
* mode. You can set it by "fsl,wdog-reset" in dts.
* For i.MX6SX we have to trigger wdog-reset to reset QSPI-NOR flash to
* workaround qspi-nor reboot issue whatever ldo-bypass or not.
Is there something similar to watch for on the imx6ul? Here is comment from mxc_restart in "arch/arm/mach-imx/system.c"