this firmware adds support for the gain, play direction and playmode settings of the OP-1 sample format. in older firmwares, these settings were ignored. this might lead to your patterns sounding different if you are using custom samplepacks. the most likely culprit will be the playmode setting. the OP-1 defaults to GATE, while the OP-Z used to treat everything as RETRIG. Adjust your playmode setting on each sample to RETRIG, to get it sounding like before.
if your track levels change due to the gain setting, either adjust the track volume, or adjust the per sample gain value.