"unexpected operator" during install with poudriere firmware image

[bodems]

When I try to install the BSDRP poudriere firmware image to an m.2-SATA SSD, I get the following error:

[root@router]/# camcontrol devlist
<AHCI SGPIO Enclosure 1.00 0001>   at scbus8 target 0 lun 0 (ses0,pass0)
<WDC WDS120G1G0B-00RC30 Z3311000>  at scbus9 target 0 lun 0 (ada0,pass1)
<AHCI SGPIO Enclosure 1.00 0001>   at scbus15 target 0 lun 0 (ses1,pass2)
<USB Flash Disk 1100>              at scbus16 target 0 lun 0 (pass3,da0)
[root@router]/# system install ada0
[: ==: unexpected operator
/usr/local/sbin/system: arithmetic expression: expecting primary: " 1 +  / 2048 "