Idea for quickly testing on real hardware

[ChocolateLoverRaj]

This is how I currently test on real hardware (based on edition 3):

• I plug in my Ventoy USB drive to the computer that I code on
• I copy the .img file that build.rs created using bootloader to the Ventoy
• I unplug the Ventoy USB and plug it into my Chromebook (robo360) which is running MrChromebox UEFI firmware.
• I boot Ventoy and select my os.img

I have an idea that won't need constant plugging / unplugging and file copying:

• A Rasbperry Pi Pico acts as a storage device
• On the test device, boot from the RPI Pico.
• The RPI Pico is connected to the development device using UART connected to a UART to USB converter or another RPI Pico, which is connected to the development device through USB.
• The RPI Pico asks the development device to provide the section of the disk that the UEFI firmware is asking for.
• A Rust program on the development device communicates with the RPI Pico and reads from the my os.img file.
• The my os.img file gets streamed from the development device to the RPI Pico to the test device.

I haven't actually tried this yet since I can use QEMU for everything for now. I have a few questions:

• Would this work? Can the UEFI firmware boot from a RPI Pico which is pretending to be a flash drive?
• At what kernel size would this method be too slow? Since the RP2040 can only do 12Mbps.
• Are there any better ways of testing without so many manual steps?

[tsatke]

IDE (which is probably the first hard drive driver that you implement) has a max speed of 5MBps (with the most basic setup), which is fast enough for probably the first few months/years of development, until you need something faster because files become bigger.

12MBps should be plenty IMO.

PXE

You could look into network booting, like PXE. It's something I've been thinking about lot about, but not actually done. I'd be interested in the results if you go for it (however the setup would look like).

SCSI

You could probably also boot from a SCSI device. I imagine the setup quite difficult, but this would be my plan b if the 12MBps really isn't enough.