Backup with Storeonce FC connection is hanging at "Loading medium from slot..."

BMA seems ok to issue "D2dOpenCommandSession" call:
[ 64] D2dOpenCommandSession: commandSession: 0x7ffec9acf770
[364] D2dOpenCommandSession: calling open command session

[299] 2020-04-16 13:12:55.080 ("/ma/sys/SystemD2DV6/system_D2DV6.c $Rev: 56356 $ $Date:: 2017-01-27 07:30:09 ":433)
[299] <<=== (7) }  /* D2dOpenCommandSession */
[299]   RetVal: Returning: 0

however, nothing returns from that call:

(local 13:12) : INFO : 38255_3268179744  : 1 : C : MMA : osCltCmd_OpenCommandSessionInternal : Ln 157 : ---------------
Entering osCltCmd_OpenCommandSessionInternal[Non-Teamed]. Session ID : -1 ---------------

eventually the Storeonce Hardware engineer indicate the new Storeonce firmware require a new objectstore library from DP end