U-boot console problem

Bits per second: 115200
Data bits: 8
Stop bits: 1
Parity: None
Flow control: None

I got this

▒a▒U▒▒▒ѠL)▒BZ▒▒▒ ▒▒▒ ▒▒▒:▒N'▒▒C▒H(▒▒f¡n▒▒▒J▒u▒▒K5▒C!▒5i ▒▒(H▒▒▒r▒٧▒A▒K▒1▒▒▒*▒▒ҕ▒▒,▒�▒▒
 ͡ .K▒ ʔ▒▒▒NV▒ݵ▒▒=▒▒H▒+▒▒▒j      5▒U▒kA▒YVլ*▒Z▒▒˕▒tC▒H▒I▒▒▒▒Y▒+▒5▒▒▒i▒▒Y▒+▒5▒Q.i▒sY▒+▒5▒▒Y▒▒
▒▒vX+▒ XV▒▒▒J▒A▒+▒᮪▒▒▒▒▒▒Y▒▒A▒▒Ѡ▒▒΁i▒2▒ų▒       *▒i▒2▒▒▒▒▒d.▒▒
                          ▒Ѳ▒▒▒:▒▒▒E▒▒▒ ▒▒▒▒]1LSHhѨ▒ ▒Ґ▒▒▒i0N'▒a▒C▒ݷ&z▒▒5▒▒▒!▒▒▒▒Y+҂▒Ұ▒ڦ'▒▒,'▒5▒&▒
!e▒+▒▒         XK▒I▒%▒ݟZ▒▒▒+▒5▒PJ5▒▒▒ ▒ٮ▒Ů▒i▒▒▒▒ʅ▒▒6▒nVմ"▒▒C▒a▒S▒▒ߡy5մ▒

Bits per second: 115200
Data bits: 7
Stop bits: 1
Parity: None
Flow control: None

I got this

-"oot .1.4(Sep 21 2015 - 17:19:07)

A121 (a29330     U-b/ot

DA-:  6 MB
led 4urni.g on for 1s...
i$ rea$ x10000&f
f,a3h 3i:e 414304
 sec4or c/unt = 64
Flas(:  4 MB
sing defa5lt e.v)ro.m%nt

In:    s%rial
Out:  s%r)al
%rr:  s%r)al
N%t:  ag720_%n%t_)n)tial)ze..
No vali$ add2ess )n Fl!sh. sing f)xe$ !dd2e3s
N/ v!l)d !d$ressin F,ash.Usin' fix%d ad$ress
: cfg1 0x5 c&g2 087114
e4h: 0003:7&:09:b:ad
eth0 up
: cf'1 0x& cfg2 0x7214
%th1: 00:03:7f:090b:a$
!THRS6: r%sett)ng s26
AHRS26: s26 res%t do.e
%th1 5p
e4h0, %th1
a5t/ u0d!te f)rm7a2e: i3_a5t/_upl/ad_f)rmwa2e = 0!
A5tobo/ting in 1 seco.ds

what should I do?

Try even parity?

      21."Se20Lj L
5:r4j.3J UI=oH    9':J
        +A4.+9gzY V
!Hh'4 S(K I)XkuK%K%r/+K9Q
              ] I)Xk
                    .i  IiX+
                            N%W XV4zyewUyi7+qioII*
                                                      rY.JY +M( *M)kf)d
                                                                               QdnVM Z
      21E3K     jMikA&Q i%N5
                            :1bU ,VV83
aa0'::Si'iaVH!Vb0!eNu0j               "
: ,VE BA#V0]2LSHhQ(L'0'R7VJ:iadC!QhnI6_nV}i+

Bits per second: 115200
Data bits: 7
Stop bits: 1
Parity: even

4 mb flash device, you sure it's worth it?

replaced with 16MB don't worry

MR3020v1.9 64MBRam With 16MB NorFlash and v21.02

The proper setting is 115200 N-8-1. You are seeing blocks because the 8th bit reads 1 when it should be zero. Setting parity basically ignores this bit, but there are still lots of errors in the other bits occurring.

Check your ground wire. Don't power the unit from a USB port on the PC, use a separate power supply that doesn't have a common ground.

I don't think this model requires resistors to be added to make the serial port work but many TP-Link do.

1 Like

I pulled out the 10k resistor and turned on using power bank

U-Boot 1.1.4 (Se0 21 205 - 7:1907)

P21 (!r933) U-"oot

DRM:  64 MB
led turn)ng o. for 13...
id r%ad 0810000f&
fl!s( s)z% 419304,sect/r co5nt = 64
Bash:  4
U3ing $e&au,ten6i2on-e.t

In:    se2i!l
O5t:  se2i!l
E2r:  seri!l
e4:   !g724_ene4_ini4iali:e...
No 6alid addr%ss i. Fla3h U3i.g &i8ed a$dr%s3
ovali$ add2ess )n Fl!sh. sing fixe$ add2ess
:cf'10x5 #fg2 x711
et(0: 00:03:7f:09:0b:a$
%th0 5p
 c&g 08fcfg20x724
e4h1: 00:03:7f:09:0b:!d
A4HR2: 2e3et4i.g s2
AT(RS26 s26 rese4 don%
eth1 u0
%t(0, e4h1
au4o up$ate &irmw!r%: )s?au4o?up,o!d_&i2mw!r% = 0
Au4oboo4ing )n 1 3econ$s
## B/ot)n' ima'e at9f02000 ...
   Un#ompr%ssin' Ker.el I-a'e .. O

What are you using for the serial connection?

I used an Arduino with built-in USB-serial by unplugging the uP on the first device I wanted a serial connection to, and it worked fine.

A couple of years later on a different device I got the same results as you. After fruitless attempts with pull-hi/-lo resistors, etc I got one of these old Nokia phone serial cables - the blue ones work AIUI, but not similar black ones: https://www.ebay.co.uk/itm/174777286684.

The pin-outs are easily found online. After cutting off the phone end and using an old PC CDROM drive cable to get female pin connectors to solder in on the GND, TX and RX lines I had a perfect serial session :slight_smile:.