Issue link: https://read.uberflip.com/i/1490991
5177 Brandi n Court, Frem ont, CA94538 | Tel : +1 51 0 -4 9 2 -4044 | Fax : +1 510 -4 9 2 -4001 | www.l o ra -al l i anc e.org FUOTA FAQ 27. Is there a specification describing the firmware file format? What about firmware encryption? No, the scope of the FUOTA WG is to define a method to transport a large binary file to one or several end- devices safely and efficiently. The firmware file format is very much manufacturer-specific, depending on chip vendor, device capabilities, and other factors. Other standards, like IETF SUIT, are chartered to define a manifest format for firmware updates and its extensions. 28. If an end-device supports FUOTA, does that require a new certification? LoRa Alliance certification for FUOTA is ongoing work for the LoRa Alliance and will be part of the LoRaWAN Certification Test Tool (LCTT), when available. 29. How can I improve the efficiency of FUOTA? Efficiency of FUOTA can be improved by using the Delta Firmware approach. The objective is to reduce the time needed for communication and, as a result, the power consumption of the end-device. With this approach, in place of sending an entire firmware image to the end-device, the FUOTA server will only send a subset of the firmware image to the end-device. There are three fundamentally different technological approaches to generating delta firmware files and applying these files to the firmware image: patching, padding, and computation. • Patching technology inserts a jump instruction at the beginning of the block to be replaced. The replacement block is appended to the image in a free expansion area. • Padding technology adds excess memory or 'pads' around firmware blocks that may be replaced. • Computation technology processes the output from the software compiler and linker to generate optimized update instructions. It is up to the device maker to decide which technology to implement in the end-device. In general, the choice of the delta firmware technology will depend on the hardware capabilities of the end-device.