Sorry for necroposting, but that comment should be marked as the solution!

Thanks for sharing!
Here are the serial output how it looks like when executing the commands:

U-Boot 1.1.4-gf8f77125-dirty (Sat Aug 14 08:53:11 UTC 2021)

ar300m - Honey Bee 2.0DRAM:  
sri
Honey Bee 2.0
ath_ddr_initial_config(195): (16bit) ddr2 init
ath_sys_frequency: cpu 650 ddr 597 ahb 216
tap = 0x00000003
Tap (low, high) = (0x8, 0x26)
Tap values = (0x17, 0x17, 0x17, 0x17)
128 MB
Flash Manuf Id 0xc2, DeviceId0 0x20, DeviceId1 0x18
flash size 16MB, sector count = 256
Power up PLL with outdiv = 0 then switch to 3
ath_gmac_enet_initialize...
No valid address in Flash. Using fixed address
No valid address in Flash. Using fixed address
ath_gmac_enet_initialize: reset mask:c02200 
Honey Bee ---->S27 PHY*
S27 reg init
: cfg1 0x800c0000 cfg2 0x7114
eth0: 00:03:7f:09:0b:ad
eth0 up
Honey Bee ---->  MAC 1 S27 PHY *
S27 reg init
ATHRS27: resetting s27
ATHRS27: s27 reset done
: cfg1 0x800c0000 cfg2 0x7214
eth1: 00:03:7f:09:0b:ad
eth1 up
eth0, eth1
Qualcomm Atheros SPI NAND Driver, Version 0.1 (c) 2014  Qualcomm Atheros Inc.
MFR:200,DID:177
====== NAND Parameters ======
sc = 0x87ff62e0 page = 0x800 block = 0x20000
Setting 0x181162c0 to 0x78f1a100
Hit 'gl' to stop autoboot:  0 
ath> 
ath> cp.b 0x9fff0000 0x81000000 0xffff
ath> mw 0x81000050 0x646f6e65
ath> mw 0x81000060 0x7365636f
ath> protect off bank 1
Un-Protect Flash Bank # 1
ath> cp.b 0x81000050 0x9fff0050 4
Copy to Flash... write addr: ff0050
done
ath> cp.b 0x81000060 0x9fff0060 4
Copy to Flash... write addr: ff0060
done
ath> protect on bank 1
Protect Flash Bank # 1
ath>