Failure to label a fat16 partition as pmOS_inst_boot using ondev

I'm trying to install postmarketOS to a Linx 7 Windows tablet (It has 32 bit UEFI with a 64 bit cpu) Now, I can use pmbootstrap install --sdcard=/dev/sda perfectly fine, the USB gets flashed properly, and the system does in fact work (barely, but it works).

However, if I try to use pmbootstrap install --ondev --sdcard=/dev/sda, to make the USB into an installer, I run into a problem. Fat partitions have an 11 character limit to their labels, and the --ondev flag tries to make a Fat partition with a label that has more than 11 characters, I think the offending file/line is https://gitlab.postmarketos.org/postmarketos/pmbootstrap/-/blob/master/pmb/install/_install.py#L706, but in any case I am prevented from making an on device installer.

(The command that is trying to be ran and failing is mkfs.fat -F 16 -n pmOS_inst_boot /dev/installp1)

EDIT: It doesn't work even if I leave out --sdcard=/dev/sda

Thanks for your time!