The Balti-A script is not yet in Unicode. The script has a tentative allocation at U+10AA0..U+10ABF in the  Roadmap to the SMP for the Unicode Standard.

A number of proposals for its inclusion have been submitted to the Unicode Technical Committee and WG2:

1992-11-25 Balti — Rick McGowan ( Unicode Technical Report #3 R2)

1999-07-20 UTR#3: Early Aramaic, Balti, Kirat (Limbu), Manipuri (Meitei) and Tai Lü scripts — Rick McGowan, Michael Everson ( WG2 N2042,  L2/99-245)

2010-07-13 Introducing Another Script for Writing Balti — Anshuman Pandey ( WG2 N3842,  L2/10-231)