Hello, I think there is an issue with the BOOT_VOLUME setting on the config helper tool. The tool UI shows the boot volume as a percentage (i.e. 60 means 60% of volume parameter), and this 60 is emitted into the config as #define BOOT_VOLUME 60. But I think ProffieOS wants BOOT_VOLUME to be an absolute value, as evidenced by this default value in case BOOT_VOLUME is not defined:
#ifndef BOOT_VOLUME
#define BOOT_VOLUME VOLUME
#endif