I have to disagree about the PBP not being hardware hackable. But in any case
Put your favourite OS (NetBSD, yes??) on an SD card.
If you can boot to it, erase the eMMC. `dd if=/dev/zero of=/dev/rdk3 bs=8m` or Linux command to fit.
If you cannot boot to the SD card, you must switch off the eMMC, and switch it back on after the SD starts booting. Be careful: when disassembled, the PBP is very fragile, flimsy, and loose (important) parts fly out if you're not extremely careful. Then, erase the eMMC as above.
Put your favourite OS (NetBSD, yes??) on an SD card.
If you can boot to it, erase the eMMC. `dd if=/dev/zero of=/dev/rdk3 bs=8m` or Linux command to fit.
If you cannot boot to the SD card, you must switch off the eMMC, and switch it back on after the SD starts booting. Be careful: when disassembled, the PBP is very fragile, flimsy, and loose (important) parts fly out if you're not extremely careful. Then, erase the eMMC as above.