When you do long test (days or weeks) test on i.MX board and your test fails, you often wants to know what has happen with a JTAG probe.
The problem is when you have 50 boards running in parallel, you don't have the budget to have 50 JTAG debug probe.
If you do a "hot plug" of your JTAG probe, you have roughly one chance out 2 to reset your board... so you'll have to wait another couple of hour to resee the problem.
Anyway to have a reliable JTAG plug with no reset, it is really simple... cut the RESET line on your cable! then you'll still be able to "attach" to your i.MX.
On the MEK board, with a 10-pin JTAG connector, you have the cut the cable line 10 of the ribbon cable:
On the cable, cut the reset line like this:
With my Lauterbach JTAG probe, when I do a "hot plug" I never have a reset of my i.MX.