I am connecting the IRToy to an Ubuntu 18.04.4 LTS machine with lirc 0.10.0.
But it appears you did not read the documentation, namely the irtoy driver. Then you would not have...
I first tried following USB IR Toy: Configure LIRC. irrecord only got to Hold down an arbitrary button with the incantation sudo irrecord -H irman -d /dev/ttyACM1 remote.conf. It always gave Timeout (10 sec), giving up..
Use the irtoy driver, not irman! As is described in ...
mythtv's IRToy page. Both pushed me to upgrade the firmware. I had trouble telling when the device was in firmware upgrade mode. I used screen to send "$" to the device. Usually, the orange LED would come on. Sometimes, the orange LED would turn on just from physically moving the device. I tried with fw_update from jesshaas.com and dpavlin/fw_update.git. With sudo ./fw_update -e -w -v -m all -vid 0x04D8 -pid 0xFD08 -ix ../USBIRToyv24.hex I got error U2IO flash erasing: FAILED. Segmentation fault. That was a couple days ago.
The command I have been using says "flash" instead of "all".
Today, I tried things again. irrecord couldn't see any events on the first run. If I run irrecord a second time, I get "Could not init hardware (lircd running ? --> close it, check permissions)". Only unplugging and replugging allowed irrecord to get to "Hold down an arbitrary button" again....
I recommend using IrScrutinizer instead of irrecord. Supports IrToy directly, and is much easier to get to work.
If I understand correctly, whenever you issue the irtoy command, the IrToy first sends the expected signal, then goes into a coma. This coma is not bootloader mode (orange LED does not go on). The toy is un-coma-d by replugging. And it is working fine with IrScrutinizer (thanks for those nice words :-))? Right?
Does the output of lsusb (the linux command) differ between when the toy is sane and when it is in coma? What exactly is your operating system and hardware?
Another simple thing to try is with sudo and a negative nice-value, i.e..
Last resort is to solder ICSP pins to the board, and flash it with an external programmer, like the PICkit3. I had similar symptom some time ago, and did exactly that. It worked.
Problem is that "normally" a PICkit3 (or equivalent) is much more expensive than an IrToy... Bit I just Googled for "PICkit3" and found some really good prices from Asian sources. No idea it that is to recommend...