ESP-07 AT commands not working, programming works though

I did already read the thread from Stefan Frings and as I said, 
programming works flawlessly as well as the firmware update.
I also measured the power supply with a scope and did not see any 
problems with voltage dips.
It's just the AT commands on the 07 that do not work.
I will give the firmware version from Stefan a try, to see if it makes 
any difference.

As the ESP-12 works correctly with the serial monitor, I doubt that the 
line breaks are the cause.
I've also tried with putty but it did not work either.

I did flash the ESP-12 as well as the ESP-07 with the 1.5 firmware from 
Stefan Frings, but the problem persists.
Both modules did perform the flash update without errors (see 
screenshots) and the boot messages at 74880 baud look the same shown 
below.
The modules identify differently on the flash update tool as expected.
Still, the ESP-12 reacts correctly upon AT commands whereas the ESP-07 
does not react at all.
Maybe the ESP-07 is broken but then it puzzles me that the firmware 
update doesn't give any error and the previously flashed blink sketch 
did perform as expected.

1

ESP-12F@74880 _________________________________

2

load 0x40100000, len 1856, room 16

3

tail 0

4

chksum 0x63

5

load 0x3ffe8000, len 776, room 8

6

tail 0

7

chksum 0x02

8

load 0x3ffe8310, len 552, room 8

9

tail 0

10

chksum 0x79

11

csum 0x79

12

13

2nd boot version : 1.5

14

  SPI Speed      : 40MHz

15

  SPI Mode       : QIO

16

  SPI Flash Size & Map: 8Mbit(512KB+512KB)

17

jump to run user1 @ 1000

18

19

ESP-07@74880 ___________________________________

20

load 0x40100000, len 1856, room 16

21

tail 0

22

chksum 0x63

23

load 0x3ffe8000, len 776, room 8

24

tail 0

25

chksum 0x02

26

load 0x3ffe8310, len 552, room 8

27

tail 0

28

chksum 0x79

29

csum 0x79

30

31

2nd boot version : 1.5

32

  SPI Speed      : 40MHz

33

  SPI Mode       : QIO

34

  SPI Flash Size & Map: 8Mbit(512KB+512KB)

35

jump to run user1 @ 1000

I have a second ESP-07 which still has the factory firmware.
This gives me the following output @74880 baud at boot.

1

2nd boot version : 1.5  

2

  SPI Speed      : 40MHz  

3

  SPI Mode       : QIO  

4

  SPI Flash Size & Map: 8Mbit(512KB+512KB)  

5

jump to run user1 @ 1000

I did flash my 1st ESP-07 with the latest SDK from 
https://www.espressif.com/en/products/socs/esp8266ex/resources and it 
now shows boot version 1.7 while the other values are the same as above.
The AT problem is the same as on both of the ESP-07 though.
I did also flash my ESP-12 with the latest firmware 1.7 and this one has 
no problems with AT commands.

My suspicion is, that the ESP-07 either have a flash ROM problem at the 
0x1000 segment, which is the jump start address for AT commands, or the 
clock frequency for AT commands is not within the correct limits.

Thanks for the reply.
I already did flash with the python tool, but things did not change.
The output is as attached.
What puzzles me is that the debug output with 74880 baud is shown 
properly, which means that the serial port works.
I am on Windows and use the Arduino IDE and its serial monitor.
My 12F module has no problems, my two ESP-07 do not work.

If I switch the baudrate to 115200 and do a reset I get a long line with 
only gibberish without a line break and there is no "ready" at the end.
AT commands do not show any reaction.

I suspect that the 07 modules have a hardware problem and I have ordered 
2 more from another seller to see if they behave differently.