Not directly related to NuttX but I hope you don't mind me asking here. Bottom line: has anyone used any bootloader other than u-boot to allow usb dfu or RNDIS-type firmware updates, and that easily boot NuttX?
My board uses the usual SAMA5 methodology of AT91 bootstrap->u-boot->NuttX. It all works as expected, as far as running code is concerned, but I simply cannot get u-boot to enable the USB port for DFU or RNDIS functions and I need the product to have user-friendly in-field updates, ideally without me having to write any PC update software. U-boot has defeated me for over 2 weeks now, and simply refuses to even "activate" the USB (i.e. a PC never even sees the connect let alone any functionality: yes, the USB port does work for NuttX and sam-ba code flashing); device trees are the invention of the devil; and an unholy apparent mish mash of driver model and "legacy" modes; no SAM boards in the u-boot trees appearing to have relevant config options I can copy. Add to that: using latest u-boot rather than the 2020 version I currently have "working"means it won't even find a console serial port any more, the lack of response on the relevant AT91 u-boot github to questions, and I am just about ready to give up :( But I need a bootloader!
