- Using ISP requires some means to connect the external programmer to the flash chip.
- Some external flasher requires some soldering to connect it to the flash chip.
Connect to a clip
Some programmers, like the Bus_Pirate have pin connectors on them.
- Short Jumper Wires can be used to connect the programmer to the clip.
- Wires length, connection quality: Long wires, and bad connection can create some issues, so avoid them. If you can't and if you're flash chip is SPI, then lowering the SPI clock can make it work in some cases. Many programmers do support such option(Called spispeed with most of them, or divisor with ft2232_spi).