U-Boot saveenv to mmc fails - Saving Environment to FAT... Unable to use mmc 1:1... Failed (1)

So, I'm running an OrangePi Plus 2E and am attempting to save the u-boot environment to the mmc. Below is the version information:

=> version
U-Boot 2020.01-g303f8fe (Jan 06 2020 - 20:56:31 +0000) Allwinner Technology

arm-poky-linux-gnueabi-gcc (GCC) 9.3.0
GNU ld (GNU Binutils) 2.34.0.20200220

For some reason, it appears that it is unable to use mmc 1:1 (see below). I'm looking to understand why. Whenever I run ls mmc 1:1, it returns things. So, I know that partition exists. Should I be chasing down a hardware failure? Or is there an issue with my u-boot build? I'm not really sure where to begin investigating this issue.

=> saveenv
Saving Environment to FAT... Unable to use mmc 1:1... Failed (1)

=> ls mmc 1:1
<DIR>       4096 .
<DIR>       4096 ..
<DIR>       4096 lost+found
<DIR>       4096 HWML
<DIR>       4096 media
<DIR>       4096 dontpanic
<DIR>       4096 misc
<DIR>       4096 local
<DIR>       4096 camera
<DIR>       4096 audio
<DIR>       4096 data
<DIR>       4096 app-private
<DIR>       4096 app-asec
<DIR>       4096 app-lib
<DIR>       4096 app
<DIR>       4096 property
<DIR>       4096 ssh
<DIR>       4096 dalvik-cache
<DIR>       4096 resource-cache
<DIR>       4096 drm
<DIR>       4096 mediadrm
<SYM>         45 bugreports
<DIR>       4096 security
<DIR>       4096 becnch_system
<DIR>       4096 user
<DIR>       4096 system
<DIR>       4096 backup
               2 .layout_version
               0 system.notfirstrun
<DIR>  [A   4096 tmp

Thanks in advance for your help!

Solution

A quick look at the failing code in env/fat.c shows that this error might occur if the partition is formatted with a filesystem other than FAT.

The presence of a lost+found folder and the use of ls (rather than fatls) also hints that the partition may in fact be formatted with e.g. ext3 or ext4.