• SPI EEPROM
  • Intermediate
  • 10 min
  • 25X series

Recipe · Intermediate · SPI

How to dump a SPI EEPROM 25X chip

The SPI wiki documents a dedicated eeprom shell for 25X-series SPI EEPROMs with probe, analyze, read, write, dump and erase actions.

SPI EEPROM chip on an SPI bus.
EEPROMs are smaller than SPI NOR flash, but still deserve a clean probe and backup first.

Wiring View

25X EEPROM BP SPI CS#CS GPIOCLKSCK GPIOSO / MISOMISO GPIOSI / MOSIMOSI GPIOGNDGNDVCCcorrect supply
Generated from the wiring summary: 25X EEPROM to BP SPI.
Step 1

Commands

Enter SPI mode, configure the pins, then open the EEPROM shell.

Result

What success looks like

Start with Probe. If the chip is identified, dump or read from known addresses before using any write or erase action.

Troubleshooting

  • HOLD# is left floating instead of pulled high.
  • Wrong address organization or unsupported chip variant.
  • Power is wrong for the EEPROM.
  • The target board is still driving the SPI lines during in-circuit access.

Next steps

  • Make a backup before using write or erase.
  • Use Analyze EEPROM to look for recognizable content or signatures.
  • For SPI NOR flash, use the separate flash shell instead.

SPI EEPROM 25X dump FAQ

Why use the SPI EEPROM shell instead of raw SPI?

The shell knows the 25X EEPROM workflow, including probe, address size, page handling, dump, write and erase actions. Raw SPI is useful for experiments, but the shell is safer for EEPROM work.

What are HOLD# and WP# used for on SPI EEPROMs?

HOLD# can pause serial communication and WP# can protect writes, depending on the chip. Knowing those pins helps you distinguish memory behavior from normal SPI transfer problems.

How do I avoid corrupting the EEPROM?

Start with probe and read-only dump. Keep the target board from driving the SPI bus, verify voltage, and do not write or erase until you have a backup you can compare.

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