I'm running a stock unit with F/W Version A1.17 and don't have any card problems. I downloaded the A2.03 version which is supposed to improve card compatibility but have never installed it, afraid it might introduce card issues for me, if it ain't broke don't fix it. I've attached the F/W update instructions and could send the v1.17 F/W bin file if you are interested in trying that one. The attached update instructions are the same for v1.17 and v2.03...
PMD661 v.1.17 Firmware Details:
1. When unit is restored after abnormal termination, data's chunk might not be correct.
2. Malfunction might occur when using an SD card that is formatted by PMD661 in other equipment.
Previous firmware versions resolved issues below:
1. By using pitch control, the unit locks up at audio files recorded at 24 bit 96 kHz.
2. EDL marks corrupt file date created properties.