December 15, 2025

Another look at the Fire3

The Fire3 is the "NanoPi Fire3". Along with the NanoPi M3, it is a board based on the Samsung S5P6818 chip with 8 cores.

The 8 cores are a pair of 4-core A53 clusters, which we have seen in other products.

The chip actually seems to have been designed by Nexell. Nexell is a partner company to Samsung, in particular doing SoC design for the automotive sector.

In the U-boot sources I have for the Fire3, I see board/nexell and arch/arm/mach-nexell. There is also board/samsung, but no arch/arm/mach-samsung

I'll note in passing that when the board boots up I see bl1 announce itself, but not bl31. I do not see samsung or nexell mentioned in the list of recognized platform ports. I have a source tree for bl1 in my collection from 2018, but I don't see this available online in 2025.

What about psci support for starting secondary cores? Is this available from bl1? Is it needed? Will the SD card I have still boot and run linux

I have U-boot source tree unique to the Fire3 also. I see two defconfig files in it that mention the s5p6818: 

configs/artik710_raptor_legacy_defconfig
configs/s5p6818_drone_defconfig:
I am not sure what I used to build U-boot for the Fire3 back in 2018. I will have to dig through my notes.

Interrupts and the Fire3

I had some notes that suggested that I managed to get interrupts working on the Fire3. And further investigation indicates this is true! Like my other boards, code gets launched by U-boot at EL2. Unlike my other aarch64 boards, the IMO bit in the HCR is set, allowing IRQ interrupts at EL2.

I verified all of this 12-17-2025. I also discovered that I have a Kyu port for this board.

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org