How does the u-boot log continue?
Although the is a warning, that log looks normal so far. Netgear has not initialised the u-boot environment and u-boot complains about it, but it should continue forward.
It should continue after the warning message. This is a normal boot from my 3800:
U-Boot 1.1.4 (May 27 2011 - 14:58:01)
DNI HW ID: 29763654 flash 16MB RAM 128MB (ar7100) U-boot dni25 V0.1
DRAM: b8050000: 0xc0140180
128 MB
Top of RAM usable for U-Boot at: 88000000
Reserving 265k for U-Boot at: 87fbc000
Reserving 192k for malloc() at: 87f8c000
Reserving 44 Bytes for Board Info at: 87f8bfd4
Reserving 36 Bytes for Global Data at: 87f8bfb0
Reserving 128k for boot params() at: 87f6bfb0
Stack Pointer at: 87f6bf98
Now running in RAM - U-Boot at: 87fbc000
id read 0x100000ff
flash size 16MB, sector count = 256
Flash: 16 MB
*** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
Net: ag7100_enet_initialize...
CHH:mac: 0 if: 2
CHH:mac:verify: 0 if: 00000002
: cfg1 0xf cfg2 0x7014
in rtl8366s_phy_setup mac=-1476803788
after rtl8366s_initChip ret=0
eth0: 74:44:xx:xx:xx:e7
eth0 up
CHH:mac: 1 if: 1
CHH:mac:verify: 1 if: 00000001
: cfg1 0xf cfg2 0x7014
in rtl8366s_phy_setup mac=-1476803308
eth1: 74:44:xx:xx:xx:e8
eth1 up
eth0, eth1
Trying eth0
: unit 0 phy is up...RGMii 1000Mbps full duplex
#259:ag7100_set_mac_from_link
: pll reg 0x18050010: 0x11110000
: cfg_1: 0x1ff0000
: cfg_2: 0x3ff
: cfg_3: 0x8001ff
: cfg_4: 0xffff
: cfg_5: 0xfffef
: done cfg2 0x7215 ifctl 0x40605060 miictrl 0x22
Client starts...[Listening] for ADVERTISE...checksum bad
checksum bad
checksum bad
TTchecksum bad
checksum bad
checksum bad
T
Retry count exceeded; boot the image as usual
nmrp server is stopped or failed !
Hit any key to stop autoboot: 0
Verifying Checksum ... OK
### SQUASHFS loading 'image/uImage' to 0x80800000
### SQUASHFS load complete: 1029363 bytes loaded to 0x80800000
## Booting image at 80800000 ...
Image Name: MIPS OpenWrt Linux-3.10.13
Created: 2013-10-09 14:31:56 UTC
Image Type: MIPS Linux Kernel Image (lzma compressed)
Data Size: 1029299 Bytes = 1005.2 kB
Load Address: 80060000
Entry Point: 80060000
Verifying Checksum ... OK
Uncompressing Kernel Image ... OK
No initrd
## Transferring control to Linux (at address 80060000) ...
## Giving linux memsize in bytes, 134217728
If it runs into a bad firmware flash, it should notice it and go to TFTP recovery mode.
Even if you have a serial connection, it will probably be easier to recover with the TFTP flash. Monitor the boot process via serial log and if the router goes into the TFTP recovery mode, just config your PC to have a fixed IP address 192.168.1.2 and use TFTP to send either a Openwrt factory.img firmware or an original Netgear WNDR3800 firmware. If the router is in the TFTP mode, you can simply just upload the firmware. No need to push any buttons etc.
This is a problem a year ago, from which I recovered via the TFTP mode:
: done cfg2 0x7215 ifctl 0x40605060 miictrl 0x22
Client starts...[Listening] for ADVERTISE...checksum bad
Tchecksum bad
checksum bad
Tchecksum bad
T
Retry count exceeded; boot the image as usual
nmrp server is stopped or failed !
Hit any key to stop autoboot: 0
Verifying Checksum ... OK
### SQUASHFS loading 'image/uImage' to 0x80800000
lzma_fs returned unexpected result 0x1
SQUASHFS error: squashfs_readdir: read_block
### SQUASHFS LOAD ERROR<0> for image!
Trying eth0
: unit 0 phy is up...RGMii 1000Mbps full duplex
#259:ag7100_set_mac_from_link
: pll reg 0x18050010: 0x11110000
: cfg_1: 0x1ff0000
: cfg_2: 0x3ff
: cfg_3: 0x8001ff
: cfg_4: 0xffff
: cfg_5: 0x2fffef
: done cfg2 0x7215 ifctl 0x40605060 miictrl 0x22
The Router is in TFTP Server Firmware Recovery mode NOW!
Listening on Port : 69, IP Address: 192.168.1.1...
Rcv:
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..........
Done!
Bytes transferred = 5374085 (520085 hex)
Erase 7 - 120 sectors...
First 0x7 last 0x78 sector size 0x10000 120
Copy image to Flash... write addr: bf070000
Done
Rebooting...
(Last edited by hnyman on 8 Feb 2014, 18:30)