imx8mn SPL serial output does not work after powerup

[Heiko Thiery]

Hi,

After a powerup the SPL output is not seen.

[Powerup]
Core:  140 devices, 19 uclasses, devicetree: separate
WDT:   Started watchdog at 30280000 with servicing (60s timeout)
MMC:   FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... *** Warning - bad CRC, using default environment

In:    serial at 30890000
Out:   serial at 30890000
Err:   serial at 30890000
Net:   eth0: ethernet at 30be0000
Hit any key to stop autoboot:  0
u-boot=>

Only after a softreset the output from SPL can be seen.

u-boot=> reset
resetting ...

U-Boot SPL 2022.07-rc4-00012-g4b48844ba4 (Jun 13 2022 - 21:06:16 +0200)
Normal Boot
Failed to find clock node. Check device tree
Trying to boot from BOOTROM
image offset 0x8000, pagesize 0x200, ivt offset 0x0
NOTICE:  BL31: v2.6(release):v2.6-5-g9b1a4d832
NOTICE:  BL31: Built : 14:03:53, May 10 2022


U-Boot 2022.07-rc4-00012-g4b48844ba4 (Jun 13 2022 - 21:06:16 +0200)

CPU:   Freescale i.MX8MNano UltraLite Quad rev1.0 at 1200 MHz
Reset cause: WDOG
Model: NXP i.MX8MNano DDR3L EVK board
DRAM:  1 GiB
Core:  140 devices, 19 uclasses, devicetree: separate
WDT:   Started watchdog at 30280000 with servicing (60s timeout)
MMC:   FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... *** Warning - bad CRC, using default environment

In:    serial at 30890000
Out:   serial at 30890000
Err:   serial at 30890000
Net:   eth0: ethernet at 30be0000
Hit any key to stop autoboot:  0
u-boot=>


Can anyone confirm the behavior?

--
Heiko