esp8266 boot up message

[yangyang]

I'm the freshman about learning ESP8266.
After I download the first code,and make esp8266 in flash start mode.
But I find the log message as shown blow:
ets Jan 8 2013,rst cause:1, boot mode:(3,6)

load 0x40100000, len 212, room 16
tail 4
chksum 0xef
load 0x00000000, len 0, room 4
tail 0
chksum 0xef
ho 12 tail 0 room 4
load 0x00000000, len 0, room 12
tail 0
chksum 0xef
csum 0xef
csum err
ets_main.c

I have seen some description about the log in doc<esp8266_non_sdk_api_reference_cn>,likeif chksum == csum means flash read ok .
but i don't know csum err means what?
Besides can you tell me where i can find more detail description about how analysis the log message.

[pratik]

Hello,

The csum error message means that there was a checksum error for the BIN files you loaded. Please make sure that your BIN addresses, lengths and flash size settings are correct BOTH during programming using Flash Download Tool AND also that you compile the BINs using the same flash settings.
If you still get the error, seems like your flash chip or flash-ESP8266 wiring has problems!

[yangyang]

Thanks for your reply,I will check the address and the flash chip.And can you tell me where I can get the information about"csum error message means that there was a checksum error for the BIN files you loaded."?

[yangyang]

Hi,i download the code again,and change a new 3.3v power.
And i saw the starting log message
"ets Jan 8 2013,rst cause:1, boot mode:(3,7)

load 0x40100000, len 31320, room 16
tail 8
chksum 0x69
load 0x3ffe8000, len 2132, room 0
tail 4
chksum 0x44
load 0x3ffe8860, len 7712, room 4
tail 12
chksum 0x11
csum 0x11
rf cal sector: 120
rf[112] : 00
rf[113] : 00
rf[114] : 01"
Well, it,s ok ,thank you.
Also,I really want to know how to analysis the starting log message.

[pratik]

Glad it worked, and we will consider releasing an application note on the startup log, thank you for the suggestion!
It is simple, by the way. You have various load addresses and their checksums printed during boot, meaning that the BIN files are present, instead of a blank flash or random junk. Once that is verified, it prints the sector number where RF calibration parameters are stored. This is new and has been implemented in the very latest SDK versions. And the other 3 parameters are related to RF calibration policy or settings.