I have just released a new version of the vgm player, V3.42. It fixes a serious bug that I missed with the previous version. Also adds support for V1.61 and V1.70 vgm files.
The bug was this: writing misaligned data to the rom. It turns out that the emulator I use for testing allows reading of misaligned data (Kega Fusion). This emulation inaccuracy is not a bug, it is performance optimization. Original software would never perform misaligned reads as it is a fatal error, so there is no need to pay the cost to emulate it.
When one forgoes real hardware testing one shall get bitten eventually.