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When working with low-voltage chips, the internal 10k pull-ups of the Bus Pirate might be too high. In such cases, it's necessary to create an external pull-up using lower-value resistors. For this, you can use the 'hiz' parameter. This way, the Bus Pirate will operate as an open drain with 'pullups=off' So, why not just use the 'pullups=on' option for this scenario? I'm trying to prevent a very typical human error in the training sessions I conduct. For example, in the previous session, a user might have left the VPU (vextern) connected to 5V, and now they need to access a 1.8V chip. If 'pullups=on' is used, the following will happen: 5V (VPU) --> CD4060 --> 2K (internal Bus Pirate) --> MOSI target chip. By having the option to set a 'hiz=on', this can be avoided. Since the pull-ups will remain deactivated while the Bus Pirate will function in an open-drain mode Return init error for invalid values of pullups, hiz, psus. Previously, invalid values of the params pullups, hiz, psus were handled as "off" (i.e. disabled). This created a potential human error when users were running flashrom with e.g. pullups=1 and expected pullups to be on, while the value 1 was handled as invalid and off. Change-Id: I6d9909b23782ef3fcb1428fd127dae0d6b211855 Signed-off-by: David Reguera Garcia <dreg@rootkit.es> Reviewed-on: https://review.coreboot.org/c/flashrom/+/79299 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>