fw_printenv works but fw_setenv does not after switching to linux-fslc-imx 5.10.69 from linux-fslc-imx 5.4.114

Hi,

I'm using u-boot U-Boot 2019.04-4.19.35-1.1.0+g4d377539a1 in pre-programmed
NOR flash and was using linux-fslc-imx 5.4.114 kernel and
fw_printenv/fw_setenv were working fine.

After upgrading to linux-fslc-imx 5.10.69, fw_setenv will not change any
u-boot variable.  fw_printenv looks like it is working ok.  I've verified
all my .config settings are the same with regard to MTD etc as my older
5.4.114 kernel.

Any ideas what could be broken?

I'm using a Dunfell based rootfs for our main system.  I did a hardknott
build of core-image-base in order to build linux-fslc-imx 5.10.69 and when
I realized fw_setenv wasn't working with Dunfell rootfs and 5.10.69 kernel,
I built hardknott core-image-base rootfs with libubootenv package added to
CORE_IMAGE_EXTRA_INSTALL thinking I'd copy over fw_printenv/fs_setenv and
libubootenv and that would probably solve my issue ... but it doesn't
include fw_printenv/fw_setenv (but libubootenv is there) in the rootfs so I
don't understand what all is going on here.

Been using fw_printenv/fw_setenv since like ... forever and haven't run
into something like this before that I can remember.

Regards,

Brian