R-JTAG GUIDE - QSB Modification for R-JTAG

Martin C

VIP Member
Jan 10, 2004
Scotland, UK
It appears that a number of people are soldering points on QSBs for R-JTAG when they're not needed.

I've therefore assembled this guide on how to prepare your QSBs for the easiest installation possible.

To start, here are the two QSBs in question:

1. J2B1 NAND QSB (Supplied with R-JTAG Ultimate kit).

The one in the image doesn't match the newer style QSB, but fundamentally they're the same : The long 'arm' to get to STBY_CLK.


Both these QSBs have points which solder to SMDs (or SMD pads) and frankly don't need to.

So let's start with modifying the NAND QSB for J2B1.

We're literally going to chop the end of the QSB off:

You don't HAVE to chop it off - you could leave it unsoldered. By cutting it off, you remove the temptation to solder it.

Next, we'll modify the JTAG QSB:

Cut along the red line.

It will look like this:

You now install as normal, but remembering this is for AUD_CLAMP use only. You can either bridge 1 & 3 as per the guide, or just solder a wire from the point in red to Q2N1. All consoles are fine to use AUD_CLAMP - there should be no need to use any other variation (in fact it's highly recommended you use AUD_CLAMP on Zephyr consoles).

Hopefully this will avoid unnecessarily lifting of the small points these QSBs would normally solder to.


VIP Member
Jun 12, 2011
Baltimore, MD
I've done the jtag board cut before to make things easier. I first tried it on a board that someone had trace repaired R2P12 and the repair got in the way of the board. Good heads up for people for trash there PHATs trying to solder those 2 points.


VIP Member
Dec 8, 2011
JTAG QSB final.jpg the zephyr board im doing right now does not have a pad to where the part i circled in green is. where is the alt point that i can solder to with a wire?