FrSkyX2/D16 bug: binding an XM receiver won't work anymore since 1.3.3.33

[egonl]

While binding a FrSky XM or XM+ receiver works fine in 1.3.3.20, I can't get a successful bind in 1.3.3.33 or 1.3.4.0.

Steps to repeat:

• Flash 1.3.3.33 or 1.3.4.0
• Power up the XM while holding the bind button. The LED stays solid red
• Press Bind on the transmitter
• The LED stays solid red. If binding is successful, it should start blinking.

Equipment used:

• FrSky XM ACCST 2.1.2 FCC
• Taranis Q X7 on OpenTX 2.3.15
• iRangeX IRX4+ with Multiprotocol 1.3.3.33 or 1.3.4.0

[rogerq]

I confirm this issue exists even on EU LBT version.
I suspect the commit that updated bind sequence to support newer receivers like Archer series broke XM+

commit a41123d "FrSky Archer Bind"