Attn: Current and prospective FiiO M11 owners (Kindly read the following carefully before use): Since its release, the FiiO M11 has received positive response from the market. Following the success of the trial sales in China (and small batch of trial sales on FiiO Aliexpress store), we have also received significant feedbacks from early adopters. We will be looking into the feedbacks based on which, we continue to improve the overall performance of the M11 via firmware updates. It has come to our attention that amongst the feedback received. There is a case of abnormalities involving a Lexar 512GB micro SD card when used in the micro SD slot 1 on FiiO M11, often resulting in occurrences of write-protection or inability to detect the micro SD. Following our investigations, please find below our observations on the issue: 1. The issue as observed occurs only on the micro SD slot 1 on FiiO M11. The issue can be attributed to the high transient current required by the Lexar 512GB micro SD card when operating at high speed, coupled with the occasional interruptions from the micro SD slot 1, often resulting in abnormal operations. 2. Based on the tests performed by our engineering team and our customers. Micro SD cards from Kingston, Samsung, Sandisk, and Toshiba functioned well without any issue on both the micro SD slot 1 and 2. The team has also performed tests on large capacity (≥128GB) high speed micro SD cards from the respective and found no issues with both the micro SD slot 1 and 2. Following consultation with Lexar coupled with further testing and investigation, the engineering team have identified the issue and the solution to the issue. 1. 512GB micro SD cards are recently introduced on the market, the offering from some of brands requires higher than average transient current when operating at high speed. The Exynos 7872 natively supports only a single external memory expansion, on the M11. The micro SD slot 1 is expanded via a voltage level conversation chip, as such when performing high speed operation on 512GB micro SD cards, abnormalities might occur for brands which requires higher than average transient current. 2. Based on the above, we are releasing firmware 1.0.3 (*find the download link and instructions at the end of the text), through the lowering of the read/write speed on the micro SD slot 1 to reduce the transient current required, thereby preventing the occurrence of abnormality. 3. The lowering the read/write speed on the micro SD slot 1, will only result in a slight decrease in the data transfer rate and will not affect any functionality. 4. If you are using a single micro SD card, it is suggested that the card be inserted in the micro SD slot 2 for optimal performance. 5. Considering the perforation of high capacity micro SD cards, a single SD card slot should suffice the requirement of most users, moreover, majority of the offerings in the market today also sports of a single SD card slot design. In order to avoid disparity in the data transfer rate causing concerns, we are considering the possibility of removing the dual micro SD card slot design in future batches of the M11. 6. We would like to apologize for any inconvenience caused, should you require our attention, kindly contact our support team at firstname.lastname@example.org for assistance. * Download link for FW 1.0.3: >> Click here * How to upgrade the M11: >> Click here FiiO Electronics Technology Co., Ltd.