SDcard Issues GRR and GRRG


The most recent batch of SD cards used in new units were formatted at the factory with an older version of FAT32. I was unaware of this situation as the cards passed all tests with the current firmware and appears to work fine with all releases through the current MINOR version 02_07_05.

  • Those cards may be found in units shipped between Oct 12 and Dec 13, 2022. Order numbers are 127612-127903.

G-R-R led sequence.

This issue is one where the unit failed to start and displayed LED code G-R-R. It occurred on Dec 6, 2022 from 1:30am through about 2:00am GMT with some of the new units specified above. It would have happened immediately. During that window the release associated with auto-update MINOR was changed to 02_08_00. That release is a major update and is based on a newer ESP8266 core that does not support something about the older SD format of those cards.

Fortunately, I noticed it within several minutes and auto-update MINOR was reset to 02_07_05 so that no further users would be effected. Only users with the above referenced new units should have experienced failure. About 10 out of a potential 250 or so reported the problem. Most of the vulnerable users probably did not experience an auto-update cycle during that window. All of the reported incidences were with units shipped during the above period. Undoubtedly there were hundreds of MINOR units worldwide, with standard format SDcards, that successfully installed the new release and subsequently reverted to the older release when it was changed back.

The current situation is that I’m waiting for replacement cards due Monday Dec 19 to replace those in the remaining inventory. I’m manually reformatting the cards in new units that are shipping. I’ve built a version 02_08_01 that uses the older ESP8266 core and am testing to make available as an interim measure so that the significant changes in that release can be made available. It should be noted that the ALPHA and BETA phase of 02_08_00, initiated on Oct 6, has been uneventful because all of those users have SD cards formatted to the conventional standard, and they continue to run fine.

G-R-R-G led sequence.

This is a completely different thing. It’s not new, but the incidence with these newer units is unsettling. By no means is it epidemic, but there have been more than I would expect out of a couple of hundred total units in the group. This is the leading edge of a new manufacturing run, so it could be unrelated to the SD card per-se, but it is significant that most have been resolved by replacing or reformatting the SD card.

The solution:

Regardless of which of these two problems you are having, the resolution is the same: Replace or reformat the SD card. There are several ways to go about doing that.

If you feel capable, follow this relatively easy procedure: Open the unit and remove the SD card. If the card can be read with another computer, copy the contents to that computer. Reformat the card using the SD Association Reformatter or obtain a new 8-32GB SDHC card. You can contact support and I will provide one for systems purchased within the past year. Copy the contents back to the new or reformatted card or download and copy the files below to the root directory. Reinsert and restart.

SD Files (631.9 KB)

Many users are not inclined to open up their units. If you are hesitant for any reason, please don’t try. You can contact me at or via PM (Private Message) on the forum to arrange return for service. If in the US, I will provide a return label.

It makes no sense to ship the unit internationally, but if you want to do so, I will refund $20 for shipping and pay return shipping. It can take a month or more, especially from Australia. Better to find someone to do the card swap as above.


In the past, and with a recent incidence of G-R-R-G, the USB power supply was changed in the course of dealing with the problem. The USB adapters sold with the 120V kit have not been at issue. It is mostly international users using phone chargers and other USB supplies designed for battery charging. If G-R-R-G is not resolved by card reformat/replacement, consider that you may not have an appropriate power supply.


I regret that this has happened. The process of diagnosing the underlying SD problem, responding to increased forum and email support, dealing with the [very cooperative] SD card supplier and spending countless hours looking for a silver bullet has been all consuming. I also appreciate the inconvenience and disappointment of the users that have been effected. Though the bleeding has mostly stopped, there’s still a ways to go to insure everyone has a viable platform going forward. I’ll be addressing that in the new year.

Happy Holidays