#ifdef CONFIG_LBA48
        unsigned char lba48 = 0;
 
-       if (blknr & 0x0000fffff0000000) {
+       if (blknr & 0x0000fffff0000000ULL) {
                /* more than 28 bits used, use 48bit mode */
                lba48 = 1;
        }
                        /* write high bits */
                        ide_outb (device, ATA_SECT_CNT, 0);
                        ide_outb (device, ATA_LBA_LOW,  (blknr >> 24) & 0xFF);
+#ifdef CFG_64BIT_LBA
                        ide_outb (device, ATA_LBA_MID,  (blknr >> 32) & 0xFF);
                        ide_outb (device, ATA_LBA_HIGH, (blknr >> 40) & 0xFF);
+#else
+                       ide_outb (device, ATA_LBA_MID,  0);
+                       ide_outb (device, ATA_LBA_HIGH, 0);
+#endif
                }
 #endif
                ide_outb (device, ATA_SECT_CNT, 1);
 #ifdef CONFIG_LBA48
        unsigned char lba48 = 0;
 
-       if (blknr & 0x0000fffff0000000) {
+       if (blknr & 0x0000fffff0000000ULL) {
                /* more than 28 bits used, use 48bit mode */
                lba48 = 1;
        }
                        /* write high bits */
                        ide_outb (device, ATA_SECT_CNT, 0);
                        ide_outb (device, ATA_LBA_LOW,  (blknr >> 24) & 0xFF);
+#ifdef CFG_64BIT_LBA
                        ide_outb (device, ATA_LBA_MID,  (blknr >> 32) & 0xFF);
                        ide_outb (device, ATA_LBA_HIGH, (blknr >> 40) & 0xFF);
+#else
+                       ide_outb (device, ATA_LBA_MID,  0);
+                       ide_outb (device, ATA_LBA_HIGH, 0);
+#endif
                }
 #endif
                ide_outb (device, ATA_SECT_CNT, 1);