You can see the version of u-boot your system just booted with by looking at /proc/device-tree/chosen/u-boot,version. Or you just run reform-check.
If you have u-boot on emmc then it doesn’t matter what you have on your sd-card. a311d will only load u-boot from sd-card if emmc is zeroed out, for example by using reform-flash-uboot --zero emmc. I documented the behaviour for different SoMs here: document where u-boot is retrieved from by SoM (#8) · Issues · Reform / reform-handbook · GitLab
I’m afraid I cannot help you with kernel issues, that’s not my expertise.