As per my previous post above, I reached out to Lucky Miner to request a copy of the LV07 firmware but they just replied that I should buy another one, so I did.
I found a cheap new LV07 on AliExpress, which arrived 6 days later.
Connected the CP2104 UART to USB adapter & successfully downloaded the firmware.
Then uploaded to the older LV07, which at first seemed to spring into life. The display showed the expected screen, but I couldn't connect to it over its internal WiFi.
I'm still seeing various errors in the serial log, so am guessing I must've damaged something during my firmware update efforts...
E (2965) i2c.master: I2C transaction unexpected nack detected
E (2965) i2c.master: s_i2c_synchronous_transaction(872): I2C transaction failed
E (2965) i2c.master: i2c_master_transmit_receive(1097): I2C transaction failed
E (2975) TPS546.c: Could not read Vout
E (2975) i2c.master: I2C transaction unexpected nack detected
E (2985) i2c.master: s_i2c_synchronous_transaction(872): I2C transaction failed
E (2995) i2c.master: i2c_master_transmit_receive(1097): I2C transaction failed
E (2995) TPS546.c: Could not read Iout
I (3005) power_management: 24 vout: 0.00, iout: 0.00
E (3005) i2c.master: I2C transaction unexpected nack detected
E (3015) i2c.master: s_i2c_synchronous_transaction(872): I2C transaction failed
E (3025) i2c.master: i2c_master_transmit_receive(1097): I2C transaction failed
E (3035) TPS546.c: Could not read VIN
I (3035) EMC2302: GET-Fan Speed[0] 431 = 4561 RPM, MSB 0x0D
I (3045) power_management: Board Temp: 27, 26
E (3045) i2c.master: I2C transaction unexpected nack detected
E (3055) i2c.master: s_i2c_synchronous_transaction(872): I2C transaction failed
E (3065) i2c.master: i2c_master_transmit_receive(1097): I2C transaction failed
E (3065) i2c.master: I2C transaction unexpected nack detected
E (3075) i2c.master: s_i2c_synchronous_transaction(872): I2C transaction failed
E (3085) i2c.master: i2c_master_transmit_receive(1097): I2C transaction failed
I (3065) power_management: TMP546_1 Temp: 0
E (3095) FreeRTOS: FreeRTOS Task "power mangement" should not return, Aborting now!
I'm therefore kinda wary of giving it another go on my new LV07, as I don't want to repeat the same mistakes.
Having read through this larger thread it seems some folk have had success, so I'm wondering if there's any pointers/tips you might be able to give?
Cheers!
Looking at the fault log, it seems there's a signal transmission issue with a TPS546. This seems similar to a problem I experienced with my LV08, which was resolved by replacing an SMD capacitor.
If you have an electric meter, you can measure the SMD capacitors near the TPS546 without power. They are generally fragile and prone to failure.
If you have two LV07s and can measure each other for reference, it will be easier to determine the cause of the problem.
I hope this article helps you troubleshoot.