Exfat is not supported by uboot…use fat16/fat32
Ok. So playing around with help I ended up with ext4 for the file system and was able to reflash my NAND.
Here is the weird bit.
I had tried flashing OpenWRT 24 onto EMMC prior to my NAND going down…I was able to boot to it, but it quit working after a couple of days and I was left with a bricked device.
Once I recovered NAND, I tried GoldenOrb for EMMC. Same thing. It worked great for like 2 days and then whammo…Wifi and the like just stopped working…and NAND was once again corrupted.
For funsies, I tried booting to the recovery in EMMC…only to discover that was my old OpenWRT 24 build.
I have restored NAND once more. Advice on moving forward?
I would like to run latest OpenWRT or GoldenOrb on EMMC…but don’t want to keep corrupting the NAND disk?
Thanks 
MT7986> nand info ‘spi-nand0’ is now active device
- spi-nand0
- device: spi_nand@0
- parent: spi@1100a000
- driver: spi_nand
- type: NAND flash
- block size: 0x20000 bytes
- page size: 0x800 bytes
- OOB size: 64 bytes
- OOB available: 24 bytes
- 0x000000000000-0x000008000000 : “spi-nand0” - 0x000000000000-0x000000200000 : “bl2” - 0x000000200000-0x000008000000 : “ubi”
After I flash EMMC, when I boot to NAND, this is what I see:
F0: 102B 0000
FA: 1040 0000
FA: 1040 0000 [0200]
F9: 0000 0000
V0: 0000 0000 [0001]
00: 0000 0000
BP: 2400 0041 [0000]
G0: 1190 0000
EC: 0000 0000 [1000]
T0: 0000 021E [010F]
Jump to BL
NOTICE: BL2: v2.6(release):
NOTICE: BL2: Built : 20:18:14, May 7 2023
NOTICE: WDT: disabled
NOTICE: CPU: MT7986 (2000MHz)
NOTICE: EMI: Using DDR4 settings
NOTICE: EMI: Detected DRAM size: 2048MB
NOTICE: EMI: complex R/W mem test passed
NOTICE: SPI_NAND parses attributes from parameter page.
NOTICE: SPI_NAND Detected ID 0xef
NOTICE: Page size 2048, Block size 131072, size 134217728
NOTICE: Initializing NMBM ...
NOTICE: NMBM management region starts at block 960 [0x07800000]
NOTICE: NMBM has been initialized in read-only mode
ERROR: BL2: Failed to load image id 3 (-2)
I guess your nand has bpi-openwrt,right? At least bl2 seems old and where bpi bl2 use propritary nmbm and maybe fixed offset to search for fip openwrt does use ubi. So maybe your nand is good again when flashing openwrt bl2 to your nand (should be offset 0x0).