Behaviour difference with Buffer.unpack between sim and hardware

Describe the bug

In the sim on makecode.microbit.org, Buffer.unpack() appears to pad undersized buffers and give a result. On hardware I get zero or an error code.

I originally hit the issue using radio.sendBuffer() and radio.onReceivedBuffer(). When sending an over length message it will get truncated, but the sim will still successfully unpack the last value if it is small, whereas on the microbit the truncated element unpacks to zero.

It would be good if the simulator matched the hardware behaviour (maybe always an error), because its easier to debug on the sim.

To Reproduce
Steps to reproduce the behavior:

input.onButtonPressed(Button.A, function () {
    let buf = Buffer.fromHex("ff");
    let arr = buf.unpack("B", 0);
    let out = "";
    for (let a of arr) { out += `${a}, ` };
    serial.writeLine(out);
    basic.showNumber(arr[0]);
})

input.onButtonPressed(Button.B, function () {
    let buf = Buffer.fromHex("ff");
    let arr = buf.unpack("H", 0);
    let out = "";
    for (let a of arr) { out += `${a}, ` };
    serial.writeLine(out);
    basic.showNumber(arr[0]);
})

Running this on the sim, both cases show 255

Running on a MicroBit V2.21 (the a hex built on makecode.microbit.org): Button A shows 255 and button B shows 0

Expected behavior
Same behaviour on the sim and hardware. An error would allow the user to find the issue faster, but a zero would at least be consistent

It would also be good for radio.sendBuffer() to give an error if the buffer is to big.

micro:bit version (please complete the following information):
MicroBit V2.21

Desktop (please complete the following information):

• OS: Fedora 43
• Browser: 1.19.13b (Firefox 150.0.3)

Start by running the supplied Button A and Button B reproduction in the simulator and on the stated micro:bit hardware, comparing Buffer.unpack("H", 0) on the one-byte buffer. Then investigate the simulator and hardware behavior for truncated buffers and oversized radio.sendBuffer() messages. Done means the simulator and hardware consistently handle undersized unpacking and the expected oversized-radio behavior is verified.