Marc,
Yep! The G900X system can be switched between FIS-B weather from the GDL 88 and the SXM weather from the GDL 69. There is a selection on the dedicated weather page in the menu to select between the two weather sources. Note, this menu selection is only available when both the GDL 88 and GDL 69 are configured in the system. The weather on the MAP page follows the selection on the dedicated weather page.
We are currently on -19 software and have verified this functionality with that software.
Thanks,
Levi