HC-05 only accepts one command after button hold/power cycle

Electronics
1

So I have an HC-05 Bluetooth module working just fine on an Arduino project using the 2.2K and 1K ohm voltage divider on the Rx line of the HC-05. I can connect it up to a 5V FTDI and talk to it, set its name, see its version, its mode, etc
AT-VERSION, AT+NAME=“new name”,etc.

But, the other 3 units in the pack of 4 I’d purchased will only accept one command. I hold the KEY(?) button down and apply power and it will only accept a command if I immediately send the command(ie have it queued in the terminal input window). From then on any following commands are ignored.

Has anyone seen something like this? These boards were purchased together and have the same firmware version.

I have ordered 5 HC-06 modules and hope they work better since I only need Slave mode for these.

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2

Maybe they differ in firmware version?
Do you have any way of asking the firmware version to HC-05 module?

3

That is what’s so odd is that the one which worked fine has the exact same firmware version as the 4 or so which no longer work. All of the new HC-06 units work as expected.

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