Bunth Tamás committed a patch related to issue #103074 : Implement Boolean Type for FB driver .
It has been pushed to "master":
It will be available in 5.4.0.
The patch should be included in the daily builds available at
http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.
From the list a of Firebird integration blockers there are only a few left
70425: EDITING: Embedded Firebird - Copying integer values from Calc to Base impossible See dependency tree for bug 70425
70506: EDITING: Embedded Firebird - Alias in queries are ignored See dependency tree for bug 70506
104316: FIREBIRD 3 : attempting to open a Firebird 3 embedded ODB database file fails to draw all UI elements, causes general LibreOffice UI malfunction