Unable to boot from USB flash drive, when another USB mass storage device is connected (LT4T 32.5.1)

Hello guys, I am successfully using USB flash drivers for rootfs, on my Jetson Nanos (have 20 of them).

Usually they are recognised as /dev/sda1 , but i rather use root=PARTUUID= in extlinux.conf, which i believe is recommended if you have multiple USB flash drivers inserted in USB3.0 ports.

And here comes my issue. When I do attach USB external SATA drive (USB3->SATA) I am unable to boot Jetson Nano After restart. And this is valid for all my Jetson Nanos . It is just stuck in NVIDIA logo screen.

I have read L4T manual over 10 times, and to my knowledge, bootloader (which is in QSPI-NOR starting L4T 32.5) should search for /boot/extlinux/extlinux.conf , find rootfs and start.

I understand that my external SATA drive is faster (so it is identified as sda) while my boot USB flash card is (sdb), but bootloader should not find extlinux.conf on sda and move onto sdb.

As far as I remove external SATA drive, I am able to boot again.

UPDATE : also when i copy /boot to /dev/sda1 (usb3-sata) , i am able to boot rootfs from USB flash (samsung flash). So it really seems that bootloader can not move on onto sdb when extlinux.conf is not found on sda ?

I have even tried to reflash QSPI-NOR ( sudo ./flash.sh jetson-nano-qspi sda1 ) also tried with sdb1 , to make sure I have latest bootloader, but it did not help.

I would appreciate any kind of help, since this is blocker for me to move onto production.

Thanks!

You should share the log.