X5-2 minimum BIOS version needed for BM 18.5.0.0.0 reimage?

Our X5-2 is currently running 12.1.2.6.0.  It has the mis-sized 100M /boot volume, therefore cannot be upgraded.  Will a BM reimage to 18.5.0.0.0 succeed with the existing BIOS/Firmware versions?   After reimaging, can the BIOS, firmware, etc. be brought up to date by applying the 18.5.0.0.0 patch?

#odacli update-dcsagent

#odacli update-server -v 18.5.0.0.0

#odacli update-storage -v 18.5.0.0.0 --rolling

Current configuration:

oakcli show version -detail

Reading the metadata. It takes a while...

System Version  Component Name            Installed Version         Supported Version

--------------  ---------------           ------------------        -----------------

12.1.2.6.0

                Controller_INT            4.230.40-3739             Up-to-date

                Controller_EXT            06.00.02.00               Up-to-date

                Expander                  0018                      Up-to-date

                SSD_SHARED {

                [ c2d20,c2d21,c2d22,      A29A                      Up-to-date

                c2d23 ]