The old isa_test.bin was generated by gen_isa_test.py which had
a wrong opcode for CNTR (0x5000AF = REG1[15] = STACKA, should
be 0x3000AE = REG2[14] = CNTR). Regenerated from isa_test.dsp
using open21xx assembler.
Also: to suppress the harmless 'asm.parser not found' warning,
use: r2 -e asm.parser=null -a adsp219x -b 24 firmware.bin
Or add 'e asm.parser=null' to ~/.radare2rc.