Bootstrap

The bootstrap workflow runs a temporary Linux system entirely from RAM, just long enough to write the real firmware onto the SPI NAND. The whole flow — FEL push, autoboot, and NAND provisioning over SSH — is driven by bootstrap.sh.

Prerequisites

• sunxi-fel cloned/built somewhere reachable (the project assumes ~/Dev/sunxi-tools/sunxi-fel; override with SUNXI_FEL=...).
• sshpass installed on the host — the board's Dropbear only does password auth (root/root), and the script runs every ssh/scp non-interactively. Override the password with SSH_PASS=....
• A USB-C cable between host and board.
• The host USB-Ethernet interface configured as 192.168.2.1/24 (the board comes up as 192.168.2.2). The script does not bring this up; configure it once the gadget enumerates.
• (optional) A USB-to-serial adapter on the board's UART (/dev/ttyUSB0, …) for monitoring.

Step 1: Build the images

make build MACHINE=network_player_bootstrap   # RAM-only bootstrap image
make build MACHINE=network_player             # production firmware to flash

Outputs land in out/network_player_bootstrap/ and out/network_player/.

Step 2: Put the board into FEL mode

1. Hold the BOOT button.
2. Press and release the f1c200s reset button.
3. Release the BOOT button.

Verify with sunxi-fel ver.

Step 3: Run the bootstrap

./bootstrap.sh /dev/ttyUSB0     # serial arg is optional (monitoring only)

What it does:

1. Drops the stale SSH host key for 192.168.2.2.
2. Pushes the bootstrap image over FEL with sunxi-fel, using the fixed RAM layout:
   • SPL+U-Boot loaded by sunxi-fel uboot,
   • kernel uImage at 0x80000000,
   • rootfs.cpio.uboot at 0x82800000,
   • DTB at 0x83A00000.
3. U-Boot autoboots on its own (CONFIG_BOOTDELAY=1) using the compiled-in bootcmd (bootm ${kernel_addr} ${ramdisk_addr} ${fdt_addr} — see uboot.bootstrap.env). The script sends nothing on the serial line; if a serial device is given it is only read, prefixed with [serial], to follow the boot.
4. Waits for SSH on root@192.168.2.2, then provisions the NAND (see below).

RAM layout

DRAM is 0x80000000–0x84000000 (64 MiB). The blocks are kept disjoint so U-Boot's relocation never clobbers a neighbour:

Block	Address	Offset	Budget
uImage source (copied by bootm to 0x82000000)	0x80000000	+0	6 MiB
kernel destination (UIMAGE_LOADADDR)	0x82000000	+32 MiB	6 MiB
initramfs rootfs.cpio.uboot	0x82800000	+40 MiB	16 MiB
DTB	0x83A00000	+58 MiB	128 KiB
initrd_high / fdt_high ceiling	0x83C00000	+60 MiB	—

Nothing sits below 0x82000000 at runtime, which avoids both the kernel-reserved low zone (otherwise the initrd is dropped with overlaps in-use memory region) and the DTB being overwritten by initrd relocation. The build warns if uImage or rootfs.cpio outgrows its budget (see post-images.sh).

Step 4: NAND provisioning

Once SSH is up, bootstrap.sh provisions the NAND automatically (commands run over SSH):

1. scp spi-nand.bin and rootfs.ubifs to /tmp on the board.
2. flash_erase mtd0–mtd3.
3. ubiformat + ubiattach mtd1–mtd3, then ubimkvol the fota / rootfs / data volumes.
4. flashcp spi-nand.bin /dev/mtd0 and ubiupdatevol /dev/ubi1_0 rootfs.ubifs.
5. reboot.

After reboot the board comes up from NAND with the production firmware. If it does not reset (some U-Boot defconfigs miss the watchdog reset driver), power-cycle it.

The manual equivalent of these steps is documented in SPI NAND flashing.

One-command bundle

make bootstrap-bundle builds both images and packs everything (scripts + artifacts) into a self-extracting makeself archive:

make bootstrap-bundle              # produces bootstrap-<version>.run
./bootstrap-<version>.run -- /dev/ttyUSB0

The .run extracts itself and executes the full bootstrap + provisioning flow end to end.