These tools apply to the DAC-HA300 and HA-P90SD, also some tools are generic blackfin tools.
Example:
$ ./onkyo_teac_tools/descramble ../firmware/HAP90-b108.130 extracted-bootstream
$ ./onkyo_teac_tools/bfin_boot -d extracted-bootstream -o fw_B108.130/
$ file fw_B108.130/*
fw_B108.130/0.elf: ELF 32-bit LSB executable, Analog Devices Blackfin, version 1 (SYSV), statically linked, stripped
fw_B108.130/1.elf: ELF 32-bit LSB executable, Analog Devices Blackfin, version 1 (SYSV), statically linked, stripped
$ ./onkyo_teac_tools/scramble extracted-bootstream > generated-image
$ md5sum ../firmware/HAP90-b108.130 generated-image
34dfd73373f6b9f92058201cd56b80a0 ../firmware/HAP90-b108.130
34dfd73373f6b9f92058201cd56b80a0 generated-image
Note that the sums won't match for the other images due to versioning information in the header. This info appears to get displayed but otherwise ignored by the firmware update program.