Just wanted to share with you my findings on a NEC 1148H floppy drive with jumpers. When using in a AT or ATX PC:

There are 8 pins that can be jumped in pairs between the power and 34 pin FDD connector.

The jumper should be jumping the 2nd pair of pins counting from the side FDD connector (see pictures). In this setting the drive will work both as A-drive and B-drive.

Also pin1 is at the edge of the drive, not towards the center, even if the notch in the circuit board indicates otherwise (at least for my FDD cable). I spent a lot of time on different PC's assuming that my FDD cable was placed correctly in the connector, because of this notch, don't do this 😀

I attached pictures of correct cable orientation and jumper placement, hoping it will help someone:

Drive A:

Drive B:

The treacherous notch: