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A Simple PC/DOS Parallel Port Based Wii NAND Programmer
TypePC utility
Version0.1 beta


I have a DIY external NAND programmer which I used it for a while as Wii NAND dumper/programmer. Some people in Chinese forum asked me to share the design to save their bricked Wii. My original design is a PCI based CPLD which cannot be DIY by most people. Therefore, I design a new PC parallel port based simple Wii NAND programmer, and modify to port my old program to the new interface. I personally will not make the new hardware by myself and the parallel port might be very low efficient for such purpose. However, the design is simple and all source codes are included so that any technical user may verify if it is feasible and provides bug corrections and enhancements.

Besides, the programs currently run on DOS environments (FreeDOS for MS-DOS). You may also help to port to Linux or Windows environments.


Most PC motherboards manufactured before one year should have build-in standard parallel port. The hardware is designed to connect to PC bi-directional parallel port.


  • DB25 male connector x 1
  • 74LVC245 x 2, identified as U1 and U2
  • 74LVC374 x 1, identified as U3
  • 48-pin TSOP to DIP socket (NAND Flash socket) x 1, identified as U4
  • 2.2K ohm resistor x1 or x5 (see Hardware Differences below)
  • Some capacitors required between 3.3V VCC and GND.

The 74LVC series components could be other TTL operating at 3.3V power with 5V tolerance I/O buffer. You will also have to generate 3.3V power by yourself or acquire it from motherboard.


  1. DB25-pin2,3,4,5,6,7,8,9 (DQ0-7) connect to U1-pin2,3,4,5,6,7,8,9 (A1-A8)
    DB25-2,3,4,5 also connect to U3-3,4,7,8 (D0-D3)
  2. DB25-1 (Strobe#) connects to U2-2 (A1)
  3. DB25-14 (AutoFeed#) connects to U2-3 (A2)
  4. DB25-16 (Init#) connects to U1-1 (DIR)
  5. DB25-17 (Sel#) connects to U3-11 (CK)
  6. DB25-11 (Busy) connects to U4-7 (R/B#)
    Also with one 2.2K ohm pull-up to 3.3V
  7. DB25-1,14,16 and 17 also pull-up to 3.3V with 2.2K ohm (could be omitted if not open-collector/open-drain output, see Hardware Differences below)
  8. U1-18,17,16,15,14,13,12,11 (B1-B8) connect to U4-29,30,31,32,41,42,43,44 (IO 0-7)
  9. U1-19(OE#) connects to GND
  10. U2-18(B1) connects to U4-8(RE#)
  11. U2-17(B2) connects to U4-18(WE#)
  12. U2-19(OE#) connects to GND
  13. U2-1(DIR) connects to VCC (3.3V)
  14. U3-2(Q0) connects to U4-9(CE#)
  15. U3-5(Q1) connects to U4-16(CLE)
  16. U3-6(Q2) connects to U4-17(ALE)
  17. U3-9(Q3) connects to U4-19(WP#)
  18. U3-1(OE#) connects to GND
  19. DB25-25, U1-10, U2-10, U3-10, U4-13 and 36 all are power ground and must connect to GND
  20. U1-20, U2-20, U3-20, U4-12 and 37 all are power VCC3 and must connect to 3.3V

Important Notes to Hardware Differences

Standard parallel port uses 5V TTL interface with 4 control signals as open-collector output. However, billions of PC have been manufactured with various ASIC chips to implement parallel ports. 5V TTL, 5V CMOS and 3.3V CMOS output designs all exist in the market. Driving CMOS HIGH at exact 5V will damage NAND Flash without buffering. Besides, some designs may drive 4 control signals as non-open-collector output so that you can omit 4 pull-up resistors. If you want to use the above full circuits, you may skip the simplification section. Otherwise, if you want to omit 4 pull-up resistors or remove the two 74LVC245 buffers, read the following section carefully.

Simplification (Read Carefully)

To omit 4 pull-up resistors in control signals DB25-1, 14, 16 and 17, you have to make sure they are not open-collector or open-drain output. You can use voltage meter to probe these signals to make sure some of them are in stable high state. If they are open-collector or open-drain, the high level will gradually reduce due to voltage meter probe sinking charge. Please note that usually PC BIOS initialize pin 1, 14, 16 as high level. You may probe these 3 pins to test.

Regarding the buffering issue, the parallel port uses standard 5V TTL interface so that we need two 74LVC245 as buffers working between parallel port and NAND Flash. There might be some simplifications we can make because, unlike standard 5V CMOS drives 5V output, standard 5V TTL output only drives HIGH level as 3.4~3.7V typically. And it happens that the operation power supply for standard 3.3V devices such as NAND Flash could be up to 3.6V. So if you have measured the HIGH level output of your parallel port is below 3.6V, you can raise your 3.3V VCC supply voltage to the same level so as to safely remove these two 74LVC245s and replace 74LVC374 with more popular 74HC374. Of course you have to bypass signals originally buffered by 74LVC245. For U1, you have to bypass pin 2, 3, 4, 5, 6, 7, 8 and 9 to pin 18, 17, 16, 15, 14, 13, 12, and 11. For U2, bypass pin 2 and 3 to pin 18 and 17.

To measure HIGH level output of parallel port, try to probe DB25-1, 14 or 16 if they are not open-collector. Otherwise you have to probe data outputs such as DB25-2,3 … 9 by first setting these outputs as high level with, e.g. DOS debug program.

-o 378 ff


The 5V TTL parallel port interface is NOT designed to safely hot-plug external devices. Never plug the programmer into parallel port if only one end is powered. The correct procedures would be as follows:

  1. Disconnect external programmer from parallel port.
  2. Power off external programmer.
  3. Put the NAND Flash into socket.
  4. Power on both PC and external programmer.
  5. Now it is safe to connect external programmer to PC parallel port.


The software include WNPID.exe, WNPDUMP.exe and WNPPROG.exe with source codes included.

  • WNPID.exe can read NAND Flash ID. It could be used to verify if your hardware circuits are functional.
  • WNPDUMP.exe is used to dump NAND to image file.
  • WNPPROG.exe is used to program NAND from image file.

All of them run under DOS which could be FreeDOS, MS-DOS, PC-DOS, Dr-DOS or Windows XP /98 formatted DOS 7.x … It is recommended you use USB or HDD booted DOS with disk caching enabled (run SMARTDRV.exe for Microsoft DOS series or LBACACHE for FreeDOS) to have better performance.

It is also suggested running WNPID first to verify your hardware and NAND Flash. Then run WNPDUMP to backup the current contents of you NAND Flash for the very first time before trying WNDPROG to restore your old dump.