Potential cost optimisation?

[emolitor]

Looking at the PCB_Rev2 design I was thinking you could avoid two of the 'extended' components which will bring down the costs of assembly with JLCPCB.

For the data line resistors I know RPI recommends (27Ω/27.4Ω) but I think 33Ω will still be in USB spec and allows you to use a BASIC JLCPCB Part (C25105) https://jlcpcb.com/partdetail/25848-0402WGF330JTCE/C25105

For the Flash you could use the BASIC JLCPCB Part (C97521) https://jlcpcb.com/partdetail/WinbondElec-W25Q128JVSIQ/C97521 although this is a much larger footprint than the uSON part on the current design. While the price is a bit higher per unit you'd need to make about 90+ boards before the lower cost of the flash per unit offset the EXTENDED Part fee.

This is just a hobby for me and I'm not a professional so maybe neither of these will work. Thank you for making this excellent design!

[nonameCCC]

For the resistor, You can surely change the resistor to 33ohm, as the package size won't vary.
But for the flash, Size is actually quite a problem to our design, especially while wiring the PCB. We've tired and actually used SOIC-8 flash in our other projects, like PH-AC. But as we need to fit our controller under the space bar and leave enough space for wire & vias, we chose the smallest packaging we could find.
Actually, the LDO we used for 3.3V power is also optimized for size (SOT-23), Otherwise we would choose the AMS1117, which has been proved pretty stable in our previous project.

[emolitor]

Makes sense, I will try 33Ω at some point and see if that work or not. Thank you.