Right guys, working on my first M1. Came in with no battery (not sure why) USBC meter 20v 0.05A. Nand underfill removed, so may have been replaced/reflowed.
I know these draw little power on bench without battery so checked DFU. Stuck in DFU so tried restore/revive both fail with error 21.
Mac DFU Wiki states following:
Error 21 - Resolved with SoC ROM replacement. On macbooks with an M1 processor, this error also means problems with NAND chips such as:
- Failure of one or two NANDs.
- Mismatch between the NAND model and the reference designation on the board (When replacing memory chips, you no longer need to write anything to them using the programmer, just follow the model/place on the board).
- Attempting to restore from recovery after replacing NANDs (After replacing NANDs, it is possible to restore only from DFU).
Is the Soc ROM the SPI/bios in the older macbooks which needs to be reprogrammed?
All voltages present on U1970 apart from SPI_SOCROM_1V8_CLK signal. I used to measure the clock on Frequency mode in the older macbooks as I don't have a scope. Not sure if this is still ok for M1's.
U1970 doesn't look as if its been removed so looks like hasn't been reflashed.
Is it worth a reflash, gentle NAND relow or any other pointers appreciated.
I know these draw little power on bench without battery so checked DFU. Stuck in DFU so tried restore/revive both fail with error 21.
Mac DFU Wiki states following:
Error 21 - Resolved with SoC ROM replacement. On macbooks with an M1 processor, this error also means problems with NAND chips such as:
- Failure of one or two NANDs.
- Mismatch between the NAND model and the reference designation on the board (When replacing memory chips, you no longer need to write anything to them using the programmer, just follow the model/place on the board).
- Attempting to restore from recovery after replacing NANDs (After replacing NANDs, it is possible to restore only from DFU).
Is the Soc ROM the SPI/bios in the older macbooks which needs to be reprogrammed?
All voltages present on U1970 apart from SPI_SOCROM_1V8_CLK signal. I used to measure the clock on Frequency mode in the older macbooks as I don't have a scope. Not sure if this is still ok for M1's.
U1970 doesn't look as if its been removed so looks like hasn't been reflashed.
Is it worth a reflash, gentle NAND relow or any other pointers appreciated.
Comment