[Sony Xperia 5 II Questions & Answers] nagae-memooff:
I am reaching out to seek guidance regarding a perplexing issue I have encountered. The second IMEI number of my device is 0, however, the device can still connect to the network as usual, and both SIM cards function normally. I am concerned this might be a precursor to unforeseen issues and would appreciate your insight. Could there be a method to restore the second IMEI? Or should this issue be overlooked?

There are some further peculiarities with my device which I'd like to bring to your attention. Please forgive any language inaccuracies, as English is not my native language. I reside in China, and recently purchased a refurbished Xperia 5II. I was initially informed by the seller that the device was a Hong Kong version. However, upon receiving it, I noticed several anomalies:

1. It appears to have originally been a Japanese version customized by KDDI. The firmware version numbers in the flashing records when I used the New Flasher were mainly 58.1.C.xx and 58.2.C.xx. And I found that "bootloader unlock allowed" is no.

2. The version number in the system settings when I first received it was 58.2.A.10.163, exclusive to the Japanese AS-42 version. However, when I attempted to 'Check for Updates', I noticed in the adb logcat that the URL identified the device's version number as 58.2.A.10.126.

3. Initially, the device could recognize both my SIM cards, but I was not able to verify if the second IMEI was already 0.

4. Google Play indicated that the "device is not certified".

Upon discovering these issues, I decided to flash the firmware using New Flasher. Having previously owned an Xperia 5II with the EEA firmware version 58.2.A.10.126, I opted to flash this EEA firmware onto the current device. As expected, I encountered a boot loop, as version 10.126 is lower than the existing 10.163 on the device.

Subsequently, I tried flashing the Japanese AS-42 version 58.2.A.10.163 firmware. Despite successful booting, I was unable to connect to the mobile network, even though the settings recognized the SIM card.

I then attempted to flash the KDDI version 58.2.C.3.127 firmware. Surprisingly, it booted normally without entering a boot loop. However, this KDDI customized firmware seemed to be designed for single-card hardware. It displayed only one SIM card, which could connect to the mobile network normally.

Given that both SIM cards were recognized and accessible when I initially received the device, I proceeded with a series of trials. Unfortunately, it would be difficult to recall every single attempt. Some memorable trials included using the Japanese AS-42 version 58.2.A.10.163 firmware as a base, and repeatedly trying to flash certain files from other firmware like the EEA or KDDI. The involved files were roughly as follows:

mdm1m9kefs1_X-FLASH-ALL-2389.sin

mdm1m9kefs2_X-FLASH-ALL-2389.sin

mdm1m9kefs3_X-FLASH-ALL-2389.sin

modem_X-FLASH-ALL-2389.sin

oem_other_X-FLASH-CUST-2389.sin

oem_X-FLASH-CUST-2389.sin

persist_X-FLASH-ALL-2389.sin

Ultimately, I was able to get a device that could normally identify both SIM cards, and Google Play indicated that the device is certified. However, after a few days, I found out that my second IMEI is 0. I speculate that some of these files might be the culprit behind the zeroing of the second IMEI. Could anyone provide further advice on this matter?