rt2x00pci_register_write(rt2x00dev, TXCSR1, reg);
 
        rt2x00pci_register_read(rt2x00dev, ARCSR2, ®);
-       rt2x00_set_field32(®, ARCSR2_SIGNAL, 0x00 | preamble_mask);
+       rt2x00_set_field32(®, ARCSR2_SIGNAL, 0x00);
        rt2x00_set_field32(®, ARCSR2_SERVICE, 0x04);
        rt2x00_set_field32(®, ARCSR2_LENGTH, get_duration(ACK_SIZE, 10));
        rt2x00pci_register_write(rt2x00dev, ARCSR2, reg);
 
        rt2x00pci_register_write(rt2x00dev, TXCSR1, reg);
 
        rt2x00pci_register_read(rt2x00dev, ARCSR2, ®);
-       rt2x00_set_field32(®, ARCSR2_SIGNAL, 0x00 | preamble_mask);
+       rt2x00_set_field32(®, ARCSR2_SIGNAL, 0x00);
        rt2x00_set_field32(®, ARCSR2_SERVICE, 0x04);
        rt2x00_set_field32(®, ARCSR2_LENGTH, get_duration(ACK_SIZE, 10));
        rt2x00pci_register_write(rt2x00dev, ARCSR2, reg);