[Core3506] Initial Flash to SPI NAND Flash Fails

2026-04-26 16:32

I have created a custom board based on the Luckfox Lyra Pi's schematic with the Core3506 module without eMMC, instead I have connected SPI NAND flash.

When I try to flash the board with rkflash (LuckFox Lyra Zero W firmware or its compiled SDK output yield the same result) it fails with this output (RKDevTool v3.31 has identical output):
❯ sudo ./rkflash.sh update
Using ./tools/linux/Linux_Upgrade_Tool/Linux_Upgrade_Tool/config.ini
Loading firmware...
Support Type:350F FW Ver:8.1.00 FW Time:2026-01-02 16:05:00
Loader ver:1.01 Loader Time:2026-01-02 16:03:32
Start to upgrade firmware...
Download Boot Start
Download Boot Success
Wait For Maskrom Start
Wait For Maskrom Success
Test Device Start
Test Device Success
Check Chip Start
Check Chip Success
Get FlashInfo Start
Get FlashInfo Success
Prepare IDB Start
Prepare IDB Fail
Note:please check flash if in the support list or welding issue

I have checked the soldering thoroughly, tried MX35LF4G24AD-Z4I and MX35LF4GE4AD-Z4I flash chips, but it did not help. The most telling thing I found is that after downloading the bootloader (from Luckfox Lyra Zero W as it seems to have the same setup), I cannot switch from the "selected storage", which is eMMC, to SPINAND (or any other option aparf ftom eMMC, but that may be expected as it is the one selected):

More observations:
1) The RK3506B appears only in maskrom mode and after flashing MiniLoader as "USB-MSC", which makes sense, as the device is not flashed.
2) When I try "ReadFlashInfo", I get that the Flash size is 0MB, but that may be due to it trying to read the default/selected eMMC.

More details:

I have also tried to tried to boot from a SD card, but that very likely failed, because I copied the update.img with "dd" and not the SDDiskTool (because it does not recognize the internal micro SD card reader in my laptop). I will likely try this again later next week, when I get my hands on an external reader.

At this point I am out of ideas, so any suggestions/help would be greatly appreciated.

2026-04-27 3:06

Based on the currently collected SPI-Flash compatibility list (available at https://lo01.g77k.com/aeb/docs/cn/Commo ... 240326.pdf), most models do not support the MX35LF4G24AD. The driver for the RK3506 is quite similar to that of the RK3576, so the test results of the MX35LF4GE4AD-Z4I on the RK3576 can be used as a reference.
We have tested the Core3506 with an SPI-NAND from the compatibility list(W25N02KVZEIR) and confirmed that it can boot successfully. You may first try flashing the miniloader.bin onto the board (without miniloader.bin, advanced functions may fail to execute), and then run "Get Selected Storage" to check whether the device is properly recognized.

2026-04-27 9:24

Thank you! I have changed the flash to a yet different one and that did the trick. Now the flashing succeeds, SPINAND is selected as the default storage, but the device is not booting from the flash and still boots into MASKROM mode. I have checked and SARADC_IN0_BOOT, SARADC_IN1_RECOVERY have 1.8 volts on them, so this should not be the cause. Just to be sure - have I overlooked something else to change apart from BR2_TARGET_ROOTFS_UBI*, RK_UBI_*, RK_FLASH_SIZE parameters?

As this could be caused by unsupported flash, I will buy W25N02KVZEIR and see if it helps.

2026-04-27 9:38

Under normal conditions, flashing the firmware image to the Luckfox Lyra Zero should allow the device to boot. Even if there are some device tree misconfigurations, it would typically still reach the kernel loading stage rather than getting stuck in Maskrom mode. It is recommended to check the debug serial output during the flashing process and confirm that the NOR flash pins have pull‑up resistors.