SMA sunny island: writing a value isn't working

[smeop]

Hi there,
I've the same issue as mentioned in the last comment of #9,
I'm writing 1 to reg 40375 (you have to choose the reg -1, so 40374) and get a "write ok".
But when reading it, it hasn't been changed. Pls. have a look:

modbus write 10.0.0.11 502 126 40374 1  
using MODBUS TCP
dev : 10.0.0.11 9600N81
addr: 126
op  : write
reg : 9DB6 (40374), data: 1
connecting...
Connecting to 10.0.0.11
[00][01][00][00][00][09][7E][10][9D][B6][00][01][02][00][01]
Waiting for a confirmation...
<00><01><00><00><00><06><7E><10><9D><B6><00><01>
write ok

isn't working, result is:

modbus read 10.0.0.11 502 126 40374
using MODBUS TCP
dev : 10.0.0.11 9600N81
addr: 126
op  : read
reg : 9DB6 (40374), num: 1
connecting...
Connecting to 10.0.0.11
reading with function code 0x03
[00][01][00][00][00][06][7E][03][9D][B6][00][01]
Waiting for a confirmation...
<00><01><00><00><00><05><7E><03><02><00><00>
reg 9DB6: 0000

Writing a 2 does the same, just 1 and 2 are allowed. Reading always shows 0, hmpf.
And the battery isn't loading.
SMA support answered: "We haven't any infos concerning that, sorry."
Fun, isn't it?

Thx a lot in advance for any hints!
smeop

[smeop]

Seems that SunSpec is the wrong choice. SMA support suggests to use SMA Modbus instead.