I understand your disapointments guys... I'm really really sorry about this mistake. I know there are several things that were not correct/perfect with the first run of Retrostone and that's really embarassing for me.
The thing is that for the RetroStone the PCB is a whole motherboard, including CPU, RAM and all peripherals. There are just so much components and schematic is so complex that I have not found these problems sooner :/
I would love to tell you that I could send everyone replacement or fix them all, but the amount of money calling back all the retrostones, rework them and reship them is not an order of magnitude the project can handle... I wish I was selling tens of millions of unit with 80% of margins as some big companies out there, but that's just not the case, I'm a very small business with low volume and margins.
About this fix, this is for the specific boot problem as follow : 
- 10-20% of time the unit will stay on blue/white LCD forever (if you have a HDMI connected you should see the message 
as on this picture "MMC: no card present" ...)
- 90-80% of time the unit boot OK.
The % seems to depend on units, some it's 5% for some others it's closer to 25 or 30% of bad boot.
This is not confirmed to work for units that crashes/freeze/boot errors with text/black LCD (I'm testing it today to see if that also fix these). If you have such unit have a look here : 
viewtopic.php?f=19&t=1760
About why I found it out, is that this resistor has no reason to be there. It's on the SD card detect trace. There is a pull up resistor on SD-detect to 3.3V, but there was a resistor connected to ground too. So instead of SD-detect being pulled between 3.3v and ground it is pulled between 3.3V and 1.7V. Now that I found it it seems pretty obvious but before finding it it was not so obvious... Reason why I put this 10k resistor in the first place is because it was in the reference schematic, but the pull up resistor value was a special component with multiple resistor of higher value(100k), so on reference schematic it was pulled between 3.3V and 0.3V (so almost ground). As other H3 boards did not used this special component I did the same as other H3 boards and replaced it with a 10k pull up resistor. Where the mistake is because other H3 boards do not have the 10k resistor to ground...
I tested to boot about 50 times on my test unit without a single boot fail. Today I will try to do the fix on crash/freeze/boot-errors-with-text/boot-error-black-LCD RetroStones and I will check if that fix the issues as well.
Doing so I will shoot a video and upload it online.
PS: if you damage the unit while doing so the warranty will be extended of course.