PS2251-09/19 XOR

On the market, it is possible to find many UFD devices based on the PS2251-09/19 controller family.

Examples include: PS2251-09-V, PS2251-09-26, PS2251-19-26.

Picture 01. Devices with these controllers

After research, we decided to create a new element for XOR searching dedicated to these devices.

In standard XOR searching, after determining the page layout, it is necessary to find the correct static XOR from our database.

This process is not complicated, but there are two main reasons to make it easier:

The XORs may differ from each other, making it difficult to determine which one is the most suitable.

Some devices may have block sizes (number of pages) that do not match any XOR available in the database.

Picture 02. No XOR key for a block with 2112 pages

Starting from Visual NAND Reconstructor 10.0, a new element called "PS2251-09/19 XOR" is available.

After determining the page layout, you simply need to connect the XOR element and run XOR key synthesis.

Picture 03. PS2251-09 element

The software will automatically generate the XOR key inside this element.

Picture 04. XOR searching

In many cases, it is difficult to find enough data blocks to generate the XOR.

However, for the PS2251-09 and PS2251-19 controller families, VNR can fill the gaps after the XOR analysis in most cases.

Picture 05. XOR searching and gaps without XOR

Picture 06. XOR after full analysis with filled gaps

Picture 07. Block from Picture 02 fully de-XORed by the PS2251-09/19 element

Conclusion

The new PS2251-09 XOR element significantly simplifies the XOR extraction process for devices based on the PS2251-09 and PS2251-19 controller families.

Instead of searching for matching static XOR keys in the database, VNR can now automatically synthesize the correct XOR and even fill missing gaps during analysis.

This improvement not only increases efficiency but also allows successful recovery in cases where traditional XOR methods fail due to unusual block sizes or insufficient data blocks.

Thank you for reading! 
Lukasz Pietrzykowski, Rusolut Team

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