I was looking for exactly this info - huge thanks for sharing!
The description looks quite similar to flashing the SPI flash in other notebooks in order to install coreboot there, so it sounds quite familiar. I was just surprised that the Pomona 5250 is supposed to fit here as I was expecting soldering to be necessary.
The only thing I did not fully understand yet: You say that supplying 3.3V from an external source is necessary because the RPI does not supply enough power to power the PBP. However, I do not understand why the PBP is powered at all during flashing? Can't this be done with the PBP being off all the time? For the SPIs I flashed on various Lenovo mainboards this was not necessary, i.e. I supplied 3.3V from the RPI and everything was fine.
Last but not least: I am pretty sure flashing can be done using a rock64 or a64 as well. If I find the time to test this I will share my experience with that.
The description looks quite similar to flashing the SPI flash in other notebooks in order to install coreboot there, so it sounds quite familiar. I was just surprised that the Pomona 5250 is supposed to fit here as I was expecting soldering to be necessary.
The only thing I did not fully understand yet: You say that supplying 3.3V from an external source is necessary because the RPI does not supply enough power to power the PBP. However, I do not understand why the PBP is powered at all during flashing? Can't this be done with the PBP being off all the time? For the SPIs I flashed on various Lenovo mainboards this was not necessary, i.e. I supplied 3.3V from the RPI and everything was fine.
Last but not least: I am pretty sure flashing can be done using a rock64 or a64 as well. If I find the time to test this I will share my experience with that.
